- 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

- continue #2140 , use the correct implementation for http requests not confuse code readers with our parsing
- fix data sender data duplication, run build test
- add note that this is actually really RAM heavy, some connection failures are not easily distinguishable from any code errors and are simply OOM.

also
- fix arduinoota prototype error when building without it (... ino2cpp, again)
- add comment about 160mhz into the platformio.ini

* Thingspeak: cleanup

* fix sync client config, refactoring

* revert changes in tspk config

* inheritance

* fix empty wificlient