Add support for BME680 using libalgobsec proprietary algorithms for precise Indoor Air Quality (IAQ) measurement. Unlike traditional CO2 sensors - and good ones are expensive - it measures nearly all VOCs compounds in the air (plus other gases) and compensates those measurements with its built-in temperature and humidity sensors to determine indoor air quality.

Co-authored-by: Max Prokhorov <prokhorov.max@outlook.com>

- 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

- don't depend on TRAVIS environment variables
- depend on CI flag to add release variables
- chmod +x

* base envs

* CI: speed up release process (since we still want some .bin files)

* fixup! CI: speed up release process (since we still want some .bin files)

* release dry run

* fixup! release dry run

* adjust

* fix .bin name

* it works

* minor cleanup for current git

* use pio suggestion about ldscript, reduce build_flags impact

* fix linker

* parse ${vars} instead of ignoring them

* add filtering and override file (sneak peak into tasmota's pio config)

* don't generate secure client (for now)

* formatting

* codacy

* PIO: remove -ota envs, handle OTA condition in extra script
* Tweak ESPURNA_BOARD variable
* Support git and latest in ota script
* Handle ESPURNA_FLAGS too
* Try to handle env and projenv in pylint
* Add deprecation comment about -ota envs
* regen arduino.h

* utils/version: use git description token as version, add memoization

* pio: move extra scripts to a separate directory

* pio: add -DAPP_REVISION=... as local build flag