The new device APIs were built on top of composition (instead of inheritance,
like the former one). At the highest level, we have `kaleidoscope::device::Base`
and `kaleidoscope::device::BaseProps`. The latter is a set of overrideable
properties, components that make up the device: the key scanner, LEDs, MCU, and
so on.
Many components - like the key scanner and LEDs - also come in a similar setup:
the base class and properties, because this allows us to make them fairly
efficient templates.
All of the existing devices have been ported to the new APIs. While the old
`Hardware` base class remains - for now, and deprecated - it is not guaranteed
to work.
Signed-off-by: Gergely Nagy <algernon@keyboard.io>