everything related to calendar time vs. system one
no need to include ntp for formatting, too

- configure magnitudes right after they are created.
  if any sensor fails begin(), this would leave .filter uninitialized
- poll on flags instead of raw timestamps.
  minor change to get rid of the init state.
- system::timer::SystemTimerFlag -> system::ReadyFlag

updated duration parser with a fixed type instead of just millis
separate decimal and floating point converter as well, try to avoid
possible precision loss with microseconds use

see #2578

* deep sleep api without ESP class dependency
* rf + cpu light sleep for cases when deep sleep cannot be used
* generic time-based light sleep; nonos does not halt cpu,
  unlike the wakeup variant. timers also keep going, so
  this has to be used with extra care

pending some 'deferred' variant and before and after sleep actions

avoid optimizing out function call when `&&` comparison is always false
resolve #2555

* globally accessible system timer class; help out with our internal
  scheduling by always using strongly typed duration and dynamic
  time adjustment for durations longer than system limits
  (see `os_timer_t` documentation)
* our own class for scheduled callbacks which are either choosing a
  simple function pointer or std function wrapper, depending on the type
  passed into the constructor. specifically for scheduled functions,
  this allows us to filter globally scheduled functions and push them to
  the front of the queue when necessary to ensure certain order of calls
* replace Ticker instances with SystemTimer
* allow types {h, cpp} in unit tests

One server implementation instead of two, plus simplify I/O operations
scheduling by processing everything in loop regardless of the server
type used.

Make it possible to accept authorization and several commands in a
single packet. If we fail the check, clients discards rest of the data.
Since we finally track connection state, debug info gets set *only* to
authorized clients.

get rid of board module, replace with system calls for hostname, board
and password. move boot (quirks) handlers to system as well
espurna::build { ... } namespace for our app const values

missing stringview key checks
fix template specialization order when building single source
update left-over modules that werent using espurna { ... }

- reduce number of resets that triggers unstable mode
- introduce a reboot reason for stability counter
  which only gets handled on soft-reset
- allow to forcibly change to either stable or unstable mode
  more explicit terminal comands to leave or enter either mode

rework more namespaces to use `espurna` root
makes internal references much easier (and shorter)

view class is not specific to settings, could use it across the app
remove duplicate code from IR

both heap size values should be u32

also rework internals of the analog and ntc sensor classes to use
explicit delays and update it's comments

Separate variables that are used just for the internal loop,
and the ones that are supposed to go into the client as args

Clean up logging and the terminal output, certain things are
now visible through the settings query and there's no need to
dump the build value

Settling on naming 'options' for enumerations (...possibly, everything
else in the future, would that make sense to store for 'setting' object)

Update terminal commands that were reporting status to also report a
full list of 'indexed' settings for the specific entity
Also updates the WebUI outputs which are (hopefuly) are already handled
as-is through the .js processing pipeline and the .html properties
receiving certain special string values

More namespacing and save ~2KiB of RAM by reducing the amount of loaded keys strings
However, ROM side of things may suffer b/c of template specializations for the
generic conversion functions when there are many different types involved.

Make sure to properly clamp delay times, as the recent issue had shown
it is possible to go below the update limit. SNTP app does not do any
runtime checks, so it's up to us to enforce these limits

Update internal random number generator from raw `secureRandom()` to a custom
'std::random_device'-look-alike, where we could also use it with STL functions
(current implementation is `os_random()` aka `esp_random()`)

No need for specific delay for each instance, just use a shared one

- BREAKING replace loadavg and system check from millis to seconds
- implement all available system clocks, make sure it is correctly
  scaled with the origin type
- fix duration::{millis(),ccount(),seconds()} and return a respective
  clock's time_point instead of duration. just like led sources, make
  sure every module stores timestamps as time_point and intervals as
  duration
- no need to track millis overflow on top of existing overflow counter
  of the micros64 in getUptime
- remove class overhead in led static delays conversion, just try to
  inline the required calculations and use NAME as unique id

also fix some non-apparent issues with heartbeat
- allow zero interval when it is also Mode::Once
- iterating runners to find the interval might return zero

- remove 'local' index and replace sensor code depending on it with the
  existing 'slot' aka 'magnitude index' used in value() and type()
- common method to store and retrieve ratios for voltage, current,
  active power and energy. default implementation is no-op, sensor
  should implement ratio adjustment & calculations to use 'slot' indexes
- re-implement 'expected' values ui. display the actual ratio values,
  and have a separate page for updating them in a more apparent way
- remove legacy settings that were adjusting expected values
- remove legacy settings that were resetting ratios and analog calibration
- generic webui action caller, add ratios and analog calibration resets

all of 'emon' sensors were updated to utilize the new approach to the
ratio handling. pulsemeter is somewhat an outlier, but it is unclear
whether removing the energy ratio is justified

terminal part was also updated
- implement `expected` command that hooks into the new ratioFromValue
  (and what webui uses to calculate ratios)
- implement `energy` command to list only MAGNITUDE_ENERGY
- remove old pzem004t commands doing ratio reset and total energy count

another global update is related to espurna::duration
- rework module-local heartbeat and led durations into a global
  espurna::duration
- update sensor internals to use specific units instead of multiplying things
  on line-by-line basis. export count() to the api

- remove public function from the header
- initial log for both states, log counted number
- fixup terminal reset triggering unstable state

- shrink utils source file, move heartbeat and boot management into system
- improvise with 'heartbeat' functionality. include scheduler implementation that will
manage the per-module heartbeat callbacks with individual 'mode' and
'interval' settings. current ones are mqtt (including relays, lights, thermostat), debug and
influxdb. preserve heartbeat NONE, ONCE and REPEAT, REPEAT_STATUS is effectively a hbReport & status bit.
- mqtt heartbeat is managed through mqttHeartbeat() callbacks
- tweak mqtt callbacks to use lists instead of the vector, slighly reducing the size of the .bin
- update WebUI, include report setting and update hbMode values
- make sure general.h settings include new heartbeat,
move constant definitions outside of the header
- correctly include dependencies through the .cpp, avoid leaking
internal details.
- as a side-effect, base headers are no longer included recursively

- general conversion from .ino modules into a separate .cpp files
- clean-up internal headers, place libraries into .h. guard .cpp with _SUPPORT flags 
- fix some instances of shared variables instead of public methods
- tweak build system to still build a single source file via os environment variable ESPURNA_BUILD_SINGLE_SOURCE

* Config: remove prototypes.h

* fixup order

* word

* add missing

* fix warning while still using .ino

* bad at c/p;