Added some utility functions and an event for tracking the state of the
USB connection.
Updated endpoints.c to select a single endpoint to send HID reports to
based on the status of the USB and BLE connections. Partially fixes#206.
Future commits will add a user setting to control which endpoint is used if
both USB and BLE are ready.
* Add back in profiles, not using Zephyr
BT identity infrastructure.
* Restore additional `&bt` commands for profile
operations.
* Fix for split pairing and subscriptions, since
Zephyr persists subscriptions across connects.
* Remove keymap from peripheral builds, reduces
firmware size, and avoids unneeded attempts
to send HID data.
* Add initial event manager implementation,
roughly mimicking Nordic's API.
* Add `position_state_changed` and
`keycode_state_changed` events.
* Hook up HID and keymap to new events
instead of using behaviour global event
crazy.