Usb => PS/2 & Gameport HAT v1.4

• Add keyboard support
• Add device emulation modes
• @Ulfenknulfen: Fix Joy Axes hardware bug which limited axes range and fixes calibration issues
• Rework and document setup mode
• Rework device input combining
• Always signal inhibited state with LED1
• Improve serial logging

Usb => PS/2 & Gameport HAT v1.3

@Ulfenknulfen: Make secondary PS/2 connector a combined connector
@Ulfenknulfen: PCB layout improvements

Usb => PS/2 & Gameport HAT v1.2

Add hardware related Readme containing FAQ