Update test framework to support `smartcam` device discovery:
- Add `SMARTCAM` to the default `discovery_mock` filter
- Make connection parameter derivation a self contained static method in `Discover`
- Introduce a queue to the `discovery_mock` to ensure the discovery callbacks
complete in the same order that they started.
- Patch `Discover._decrypt_discovery_data` in `discovery_mock`
so it doesn't error trying to decrypt empty fixture data