Add PWM Output

[brentru]

This pull request adds PWM output functionality to WipperSnapper.

Feature

• Adds a new component, ws_pwm, to WipperSnapper for PWM output
  • Used to drive new components on Adafruit IO such as the Pizeo Buzzer and Servo
• Adds new helper functions getChannel() and getInactiveChannel() to ws_ledc component.
  • Adds resolution to attachPin call.

Stability and refactoring

• Refactors buildWSTopics() to check for malloc failures immediately after allocating topic strings.
• Adds ESP32-x reset reason to serial output for enhanced debug output
• Adds new function, generateDeviceUID(), which generates device UID. This functionality was previously within buildWSTopics().
• Moves the ledc servo driver to new ledc/drivers folder

Testing notes:

• PWM should be tested w/ ESP32, ESP32-S2, ESP8266, SAMD
• Since there were changes to the ESP32-specific LEDC driver, both Servo and PWM should both be tested on ESP32

[brentru]

Tested on ESP32, ESP8266