[FR] update to PlatformIO 6.0

[rubienr]

Description

• do update the code to be compliant
  • with PlatformIO 6.0 + Unity (needs: platformio.ini update and implementation of further Unity transport, etc)
• do code cleanup so that all commands and related methods are called
  • ...setCommandXXX... and ...getCommandXXX... when commands can be used as setter and getter
  • ...doCommandXXX... when commands are only used to trigger actions