This commit adds the IRQ_GATTS_INDICATE_DONE BLE event which will be raised
with the status of gatts_indicate (unlike notify, indications require
acknowledgement).
An example of its use is added to ble_temperature.py, and to the multitests
in ble_characteristic.py.
Implemented for btstack and nimble bindings, tested in both directions
between unix/btstack and pybd/nimble.
There doesn't appear to be any use for only triggering on specific events,
so it's just easier to number them sequentially. This makes them smaller
values so they take up only 1 byte in the ringbuf, only 1 byte for the
opcode in the bytecode, and makes room for more events.
Also add a couple of new event types that need to be implemented (to avoid
re-numbering later).
And rename _COMPLETE and _STATUS to _DONE for consistency.
In the future the "trigger" keyword argument can be reinstated by requiring
the user to compute the bitmask, eg:
ble.irq(handler, 1 << _IRQ_SCAN_RESULT | 1 << _IRQ_SCAN_DONE)
