- Don't use global vars in jsmn_parse.c
- Const everything in jsmn_parse that we can to ensure we don't
  accidentally corrupt our stack pointers (buffer pointers and time var)
- Add edt char array to parser so we don't have to mutate the JSON
  buffer for atoi()
  - strtoull is still misbehaving
- Removed leaky jsmn print token function used for debugging
- Abstract out JSON helper functions to their own file
- Ensure jsmn.h defines aren't duplicated by creating jsmn.c and using
  #define JSMN_HEADER as lib docs detail

- Ensure picolibc
- Remove log info color
- Make jsmn_parse "tokens allocated" log msg debug not inf

Fix json buffer overflow and cleanup

- Increased brightness by another 10%
- Turn off all displays on boot (again)

- Changed gamma LUT to 2.0 from 1.8
- Changed route colors to closest web-safe variant because 8-bit color
- Adjusted default brightness levels for new colors and gamma
- Added new power testing mode under CONFIG_LED_DISPLAY_TEST