Ok so this is the final pull request that unifies all the changes necessary for the API transition from v2.x to v3.x arduino-esp32.

Main changes:

• MCWPM driver rewritten completely
  • made more flexible, no more slots
• Low-side current sensing rewritten completely for the new API
  • new timer synchronization code
  • made more flexible, no more hard-coded funcitons and variables
  • could support more than 2 motors (but not suggested - adc read time too long)
• ADC fast reading rewritten
  • simplified both for esp32 and esp32s variants
  • Now used by default both for mcwpm and ledc
• LEDC driver rewritten for the new API
  • Extended and made more flexible
  • now center aligned
  • now supports 6pwm
• More elaborate error reporting and debugging scheme, easier to know what went wrong

Other new features:

• I've also mad the function _driverSyncLowSide return -1 if it fails, so there are a few slight changes other mcu types, not just esp32
• I've made the functions _configureLowSide and _readADCVolatgeLowSide return -1 (and display a debugging error) by default instead of calling their inline equivalents. This is a safety measure to avoid using suing low-side current sensing if it's not available.
  • this required a slight change in the BG431 driver

The code was tested on esp32 and esp32s3 variants, so it is relatively mature.
It needs much more testing, but I think that it should be fine for the dev branch.