There's no reason for us to install everything in `out/` when all that
is really used are the firmware binary (`klipper.{bin,elf}`) and the
config file
- Add `klipper-genconf` helper to generate firmware configs
- Add `klipper-flash` helper to flash firmware to microcontroller
By default, klipper-firmware is built with a simulator config. Override
`firmwareConfig` with a generated config from `klipper-genconf`. To
flash the firmware, override `flashDevice` in `klipper-flash`.
