Workaround for the circular dependency between
`platypush.entities.bluetooth` and `platypush.plugins.bluetooth.model`.
Unentangling the circular dependency would require way too much work,
since the entity model provides several helpers and properties that
depend on the plugin's model.
The workaround in this commit is to simply push those imports down in
the methods that use them, so they won't be imported until those methods
are called, as well as removing some type annotations that depended on
those objects.
- Merged together Bluetooth legacy and BLE plugins and scanners.
- Introduced Theengs as a dependency to infer BLE device types and
create sub-entities appropriately.
- Using `BluetoothDevice` and `BluetoothService` entities as the bread
and butter for all the Bluetooth plugin's components.
- Using a shared cache of devices and services between the legacy and
BLE integrations, with merging/coalescing logic included.
- Extended list of discoverable services to include all those officially
supported by the Bluetooth specs.
- Instantiate a separate pool of workers to discover services.
- Refactor of the Bluetooth events - all of them are now instantiated
from a single `BluetoothDevice` object.
Fabio Manganiello