Initial release

Starts with support for Elro Connects alarms.
The siren platform is implemented so the alarm can be tested by turning the siren on.
The siren can be silenced by turing the siren off.

The sensor platform is implemented and adds a battery sensor and device state sensor for each connected device. A disabled sensor for the device signal is added aswell, it can be enabled manually.

Full Changelog: https://github.com/jbouwh/ha-elro-connects/commits/v0.1.0