GitLab

Previously, the MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE macro
controlled enabling both the central mode and the GATT client
functionality (because usually the two go together).

This commits adds a new MICROPY_PY_BLUETOOTH_ENABLE_GATT_CLIENT
macro that separately enables the GATT client functionality.
This defaults to MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE.

This also fixes a bug in the NimBLE bindings where a notification
or indication would not be received by a peripheral (acting as client)
as gap_event_cb wasn't handling it. Now both central_gap_event_cb
and peripheral_gap_event_cb share the same common handler for these
events.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>