Add support for equipment interlocks

[cryptk]

Currently, if there is an interlock in place, home assistant will still allow toggling the entity on, but the next time the integration polls it will go back to off.

An example of this is a relay for a water feature that is interlocked with a pool cover sensor/switch so that the water feature cannot be turned on while the cover is closed.

We should detect this scenario in the configuration so that we can surface a message to the user if they attempt to toggle a device while it is interlocked.

[Paulbhyo]

I think we can close this, or put it under "needs API support"?.

• Work arounds would be using the whyon status of the affected interlocked equipment and creating a new binary sensor in HA. (eg. whyon =10 when the valve is forced off by external interlock, if whyon = 10, interlock is on)
• Or a more backwards way about it would be to setup the Omni to control a new relay, force the relay on or off depending on the status of the interlock. Relay entities show up in existing integration as a controllable device.

[cryptk]

That's a slightly different issue (but both related to interlocks). The whyOn issue was to allow inferring the state of a sensor that wasn't reported in telemetry (because it is only used as a source for an interlock). This issue is to surface a useful error to the frontend if someone does something like attempt to turn on a water feature that currently cannot turn on due to an interlock.

You are correct though that we need some API support for this to surface that interlock data, I'll mark it appropriately.