Investigate removing YAML config

[strawgate]

We should identify if we can remove the YAML configuration without disrupting existing users.

Ideally we'd just stop pulling new settings from the YAML without breaking existing users and present a "repair" that tells them to move to UI-based configuration

[strawgate]

So I performed a test where I added an elasticsearch configuration to configuration.yaml:

elasticsearch:
  url: https://host.docker.internal:9200
  verify_ssl: false
  username: hass_writer
  password: changeme

I then removed the configuration from the yaml and saw the elasticsearch integration was still configured in hass.

I then readded the configuration to the yaml, but removed all yaml config handling from the integration. I then started the integration again.

In the logs I see an exception thrown: homeassistant.data_entry_flow.UnknownStep: Handler ConfigEntriesFlowManager doesn't support step import but otherwise the integration persists and I am now able to modify options via the UI.

So it would appear as though we can simply remove the yaml configuration and anyone who was using it is effectively migrated to UI-based management on upgrade.