[6.0] FreeRTOS, screen rewrite
What's Changed
- Introduce FreeRTOS for true multithreading on both cores on RP2040
- Rewrite screen logic to use frame buffering for a cleaner, more reliable info display (inspired by @thandal efforts)
- Dark mode is now an option - pick your theme in the config tool
- Show ESC temperature on the screen
- Allow viewing of version and run time without rebooting (hold down button while disarmed)
Code improvements
- Break out code for altimeter into CPP files
- More reliable EEPROM writes
Note: SAMD21/M0 controllers are not yet compatible with v6.0