Update quality scale of devolo Home Control

[Shutgun]

Proposed change

If I'm not mistaken, the devolo Home Control integration reached the gold quality scale.

✔ Don't allow configuring already configured device/service
✔ Discoverable
✔ Set unique ID in config flow
✔ Raise ConfigEntryNotReady if unable to connect during entry setup
✔ Entities have device info
✔ Full test coverage for the config flow
✔ Above average test coverage for all integration modules
✔ Tests for fetching data from the integration and controlling it
✔ Has a code owner
✔ Entities only subscribe to updates inside async_added_to_hass and unsubscribe inside async_will_remove_from_hass
✔ Entities have correct device classes where appropriate
✔ Supports entities being disabled and leverages Entity.entity_registry_enabled_default to disable less popular entities
✔ If the device/service API can remove entities, the integration should make sure to clean up the entity and device registry.
✔ When communicating with a device or service, the integration implements the diagnostics platform which redacts sensitive information.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request: Update quality scale of devolo Home Control integration home-assistant.io#27290

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• I have followed the perfect PR recommendations
• The code has been formatted using Black (black --fast homeassistant tests)
• Tests have been added to verify that the new code works.

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

• Documentation added/updated for www.home-assistant.io

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

• The manifest file has all fields filled out correctly.
  Updated and included derived files by running: python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt.
  Updated by running python3 -m script.gen_requirements_all.
• For the updated dependencies - a link to the changelog, or at minimum a diff between library versions is added to the PR description.
• Untested files have been added to .coveragerc.

To help with the load of incoming pull requests:

• I have reviewed two other open pull requests in this repository.

[home-assistant]

Hey there @2Fake, mind taking a look at this pull request as it has been labeled with an integration (devolo_home_control) you are listed as a code owner for? Thanks!

Code owner commands

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• @home-assistant close Closes the pull request.
• @home-assistant rename Awesome new title Renames the pull request.
• @home-assistant reopen Reopen the pull request.
• @home-assistant unassign devolo_home_control Removes the current integration label and assignees on the pull request, add the integration domain after the command.

[emontnemery]

Nice! 🎉