* Move to local/stack allocated event API that doesn't require
dynamic allocation/freeing.
* Disable heap, we no longer use alloc/free unless using LVGL.
* Tons of refactors all over to account for the new event approach.
Note there was one place where a non-strict prototype was actually being used
with an argument, in `zmk_hog_init`. In this case, the actual argument type was
added instead.
There is already a function to see if the peripheral is connected, a matching one for if it's bonded is a useful addition for displays/indicators. `is_bonded` gets reset to false in the advertising function in preparation for runtime peripheral bond clearing
* Split centrals to scan with their identity so they receive direct
advertising packets.
* Split peripherals to use direct advertising if they have an existing
bond to a split central.
* Proper usage of bt_uuid_cmp.
* Central's don't start scanning for peripherals if
`ZMK_BLE_CLEAR_BONDS_ON_START` is enabled.
* Split peripherals don't advertize if
`ZMK_BLE_CLEAR_BONDS_ON_START` is enabled.
* Add new API/status to track state of the
peripheral connection to the central.
* Add new peripheral status widget for displaying
the current status of the connection to
the central.
