Enable manual TX with the middle GPIO button

[kareiva]

Allow manual TXing using the middle GPIO button on the T-Beam.

By enabling the Config.beacon.button_tx setting, users will be able to manually trigger the beacon, if all the other update conditions are met (GPS location fixed, etc.).

Tested with T-Beam V1 and with a TTGO LoRa32 as the iGate

Used the Arduino OneButton library (found it to be successfully used in other projects on T-Beam):
https://github.com/geeksville/OneButton.git

[kareiva]

Raw packets of the testing station LY2EN-5:
https://www.aprsdirect.com/details/raw/sid/4840660

[peterus]

@kareiva please fix the two cppcheck issues and add the version-style from OneButton into the platformio.ini file (that it is looking the same as from the other libs).
other than this, i will merge this PR asap 😉

[kareiva]

@kareiva please fix the two cppcheck issues and add the version-style from OneButton into the platformio.ini file (that it is looking the same as from the other libs). other than this, i will merge this PR asap 😉

Hope the cppcheck will go through this time :) Also I think I've found a compatible library straight from platformio (https://platformio.org/lib/show/11802/OneButton) which seems to work just fine and hopefully will serve as foundation for future features, such as handling long clicks, double-clicks, etc.

Thanks for looking at this.

[kareiva]

Also with this, I assume you don't mind me moving the send_update variable to the global scope 😁