c/p PSTR attribute from Core files
dostring declaration with a macro instead of a scary looking boilerplate

saves varying amount of code space, mostly deals with our key and cmd strings

see #2544

use updated class method for comparison
same prefix did not work with exact lengths

looks like bootloader implementation avoids static and bss zero-init
does not solve the crashing, though

* make sure we don't apply hsv and brightnesss, only take hue and saturation
  when calculating inputs. use value as brightness percentage, wrapping
  the original function (which also makes other modules use this codepath)
* deduce interface elements based on both setting and incoming
  properties. wrap everything in {light: ...} in both inputs and
  outputs, alse allow to update multiple properties at the same time
* add light state toggle when special lights relay is not set up
* remove channel, state and brightness elements through css styling
  instead of going to the elements directly. no need to chech whether
  certain elements exist

generic pwm causes hwdt, needs investigation

solves edge-case when we move our storage nearby a previously erased kv,
causing it to be treated as a key or a value with length 255 (... 0x00 0xff)

also stop set() from erasing data when it is not possible to store it in
the first place

additional test case similar to permutations one, make sure keys don't
disappear while we write to the storage a lot of times and possibly
introduce the two cases above

fixing previous builds getting stuck on Sep 21st

turns out it *really* uses file modification time
updating VERSION does not change a thing, it does not work like scons :>

* stateless callbacks for mqttRegister. no module uses the lambda / std
  func with captures or otherwise, so it is kind of pointless to have it
* make sure we know topic and payload length at all invocations and
  not constantly trying to re-parse the same string over and over again
* clean-up api related to string parsing and make sure we allow
  stringview as input
* clean-up id / unsigned number parsing to work with views instead of
  using a generic strto{,u}l; sometimes this works, sometimes doesn't.
  as noticed previously with IR implementation, it *will* parse until
  the '\0' is found in the input and we can't interpret parts of the
  string without doing a copy for the strtoul
* fixing additional bugs caught in ifan, leds, sensors and lights that
  were causing build failures. plus, more range-based parsing code for
  the same reason as described above

* 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

see #2539

separate color and white channel availability from settings;
allow color, hs, mired inputs but do not send anything when those are disabled

advertise `color_mode` support, match specific number of channels
with some special mode that should be used on the remote
(which are, currently, shown in separate control tabs)

also replace external function calls that are already handled by Info

also fix typos in the pzem004t lib import

- setup uart at boot instead of delaying until some module needs it
  removes global `SERIAL_BAUDRATE` and `DEBUG_PORT` in favour or
  globally accessible numbered port configurations with `MODULE_NAME_PORT`
- automagically enable uart support for sensors that need it
- allow every sensor to configure uart0 (normal and swapped), uart1
  and an optional software-serial mode support with an extra build flag
  remove individual includes across the sensors
- settings queries and runtime port configuration (prefixed with uart)
- update dependencies header to cross-reference used ports at build time
- update deprecations header with serial baudrate notice

- clean-up comparison routines and get rid of most of the casts
- reduces total number of calls to terminalRegisterCommand
  replace with a func accepting list of commands, which in
  turn get instantiated as constexpr PROGMEM arrays
- reduce ram fragmentation, since we don't need to alloc as much
- reduce flash consumption b/c of lambda -> standalone func conversion

previous fix did not apply to builds without single-source env setup
ci builds with it enabled at all times

fix #2538

sync and async dns functions for both terminal and this

both use callbacks with IPAddress helper instead of using ip_addr_t
(at least, for now. seems like it is in need of our own wrapper, too)

amend 5bc55cd1a5

- fix initialization routine to auto-select appropriate port between
  either hardware-only serial or hardware-plus-software serial
  both depend on which TX and RX pins are selected
- allow to use 'swapped' uart0 mode with pinx 13 and 15
- software serial is no longer forced upon the user, setup depends on
  which tx and rx are used in config
- allow to either send or receive data as HEX strings
  mqtt received `616263` gets written as `abc` and vice versa
- (optional) send termination byte when writing to serial

avoid weird conversion from string -> time_t -> string

remove magic inline macros converting string value to time_t.
instead, just pick specific string regions and explicitly constexpr'ify conversion
(ref. https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html)

ntp could lose the value, since we never use it properly
(although, ctime functions do; it is rather tricky with timezones, though)

nofuss could use any value, might as well use the string that is already
provided by the compiler that has the same property as the used timestamp

blockingDelay uses inverse logic; passed function should return false
when the condition is satisfied
only broken on 2.7.x, 3.x.x skips the check

note that it is equality, not byte comparison based on
memcmp or strcmp return values