Feature/esp-now-network

[Ben-PH]

This commit gets things in a minimal PoC with the core + modules architecture:

• core: a usb-capable, esp-now capable device without any pin requirements
• modules: solely responsible for sending peripheral state to the core. Send matrix state, scroll wheel accumulator, mouse-movement accumulator, etc.

glaring omission:

• only finger module, no mouse, wheel or thumb-cluster input