Add ability to monitor relay events

[oblogic7]

Description:

Enables ability to trigger actions in Home Assistant when Doorbird relay is triggered.

Pull request in home-assistant.io with documentation (if applicable): home-assistant/home-assistant.io#7648

Example entry for configuration.yaml (if applicable):

doorbird:
  token: YOUR_DOORBIRD_TOKEN
  devices:
    - host: DOORBIRD_IP_OR_HOSTNAME
      username: YOUR_USERNAME
      password: YOUR_PASSWORD
      name: Driveway Gate
      monitored_conditions:
        - doorbell
        - motion
        - relay

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• New dependencies have been added to the REQUIREMENTS variable (example).
• New dependencies are only imported inside functions that use them (example).
• New or updated dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.
• New files were added to .coveragerc.

[oblogic7]

This is ready to go. Any reason it has sat for so long?

[balloob]

We were on a break and had over 190 open PRs, things take time…

[MartinHjelmare]

Is this return correct? It looks weird in this place. Also, nothing is checking the return value of this method.

[oblogic7]

The return is unnecessary, but shouldn't cause any problems since the calling code does not expect a return value. I have some other housekeeping tasks planned for this component and will clean this up as part of those changes.

[MartinHjelmare]

Should we really return inside the loop?

[oblogic7]

Nope. You're right. Guess I'll go ahead and knock out those changes...