Add a custom panel for KNX with a group monitor

[farmio]

Proposed change

This adds a custom panel for the KNX integration which allows to upload a project file (.knxproj) and offers a group monitor for live bus diagnostics.

More features shall follow later - this was our idea of a MVP for a custom KNX panel.

New requirements

xknxproject - the project data parser https://github.com/XKNX/xknxproject/
knx-frontend - the package containing the panels frontend code https://github.com/XKNX/knx-frontend/

Screenshots

Project information and uploader

Group monitor

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:

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 @Julius2342, @marvin-w, mind taking a look at this pull request as it has been labeled with an integration (knx) you are listed as a code owner for? Thanks!

Code owner commands

Code owners of knx can trigger bot actions by commenting:

• @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 knx Removes the current integration label and assignees on the pull request, add the integration domain after the command.

[elupus]

This is really cool and i'd love to see this in. Is panel_custom is the right way to go? Seems to be very little use of that inside HA. Panels tend to be added directly to the frontend repo.

[farmio]

That was Paulus' suggestion. Afaik it's only used for Insteon currently, and there is an open PR for Dynalite doing the same.

I guess only selected / wider used integrations get to go directly into the frontend repo.

[elupus]

Looks quite good. Would be good with some other eyes on it too.

[marvin-w]

Nice! Looks good. Tested again locally and working flawlessly. Since I was involved in the coding I'd rather not merge this on my own. This should be reviewed by ha/core.

[elupus]

I think this looks good. A second opinion from somebody with more knowledge of custom_panel would be good.

[teharris1]

I think this looks good. A second opinion from somebody with more knowledge of custom_panel would be good.

I built the Insteon side panel and this LGTM.

[marvin-w]

I'm gonna merge this since we have three approving reviews on this. Thank you all!