feat(TTY): Add Serial TTY interface source drivers and OXP Serial Driver

[pastaq]

• Adds new source device subsystem, tty.
• Adds driver for OneXPlayer OneXFly F1 and F1 Pro Serial TTY device.
• Combine the configs for F1 series.
• Add OneXPlayer X1 and its TTY device. (Closes fix(OneXPlayer X1): Add OneXPlayer X1 series. #191)

[pastaq]

Some explanation of why this is needed: The F1 series has two extra shoulder buttons (M1/M2). When the MCU is in xinput mode all events flow to the evdev. M1 and M2 are programmable, but only with the limited xinput event set. M2 is set to guide by default and no other button uses guide, but there is no "free" event for M1, leaving it unusable.

There is also a debug TTY mode. Switching to it moves all input to the serial interface (evdev receives no data) and M1 and M2 can be seen directly, along with the mapping of each button. As a side effect the joystick input is very slow compared to the evdev input. My testing shows this produces joystick events at somewhere between 15-20hz. Gameplay seems okay in this mode for platformers, racing, and FPS games, but I'm waiting for internal testing from OXP themselves if this is "acceptable". If not I'll drop the option in the config and reuse the serial port driver to configure M1 and M2, leaving M1 as a duplicate of some other xinput button (A probably).

[ShadowApex]

Mostly nits, otherwise looks good!