Add ESP32-S3 support

[pkendall64]

Using an S3 allows us to have more GPIO pins available, 45 of them, 9 of them are reserved for Flash & PSRAM, leaving 37 usable IO pins!

The following features are available all at the same time!

1. Direct USB for updates and serial output (2 pins)
2. RGB LED (1 pin)
3. 16 PWM/IO pins configurable as DShot or other IO things (16 pins)
4. VBatt ADC input (1 pin)
5. Separate CRSF serial pins, for FC or CRSF sensors (2 pins)
6. Separate I2C pins, for Vario/Gyro etc (2 pins)
7. True Diversity/Gemini (11 pins)

And still 2 pins available!

[hydra]

It should be noted that a 2nd UART is also available to be used, in addition to the usual RX uart, which is useful for things like a GPS connection, or a UART based OSD which downstream projects like @MUSTARDTIGERFPV 's FormationFlight will find useful.

And also, that unlike the PicoD4, the JTAG pins can be used as PWM pins as they're not 'strapping pins'.

[hydra]

Also, for people not following along with my new hardware design on discord, I'd like to say that I've been using the changes in this PR for a while now. The PWM changes in this PR are especially helpful.

[wvarty]

Seems pretty harmless to the existing ESP32 platform (the changes are mostly all behind #defines so shouldn't have too much of an impact). LGTM!