ESP32 Gameboy

First version of the PCB had a long list of issues and were intended mostly to validate all the hardware working together on the test stand, rather than in enclosure. Mechanically PCB needs to be 0.8mm thin, rubber buttons are not too practical for testing and many other small things are not helping testing.

It allowed however to figure out power schematics and all the necessary GPIOs. Revision B just came from the factory, and compared to predecessor
- Fix many mechanical issues
- Abandoned idea of using AA batteries and switched to Li-Ion instead
- Figured out power network
- Few fix-ups on audio, which is still not working perfectly though (Built-in DAC is not good enough even for 8-bit concerts)

All and all, it fits perfectly

Few minor glitches I'm trying to fix in the software now. Audio require more work as well.