Remove customize UI

[ludeeus]

Breaking change

Proposed change

This PR removes the "customize" UI, this is outdated and should not be used by anyone.

Type of change

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

Example configuration

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue or discussion:
• Link to documentation pull request: Cleanup customize UI docs home-assistant.io#20337

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• 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

[balloob]

For context: customization dashboard writes to a YAML file that can be included in your configuration under the customize section, which needs to be manually set up. This option is sending users in the wrong direction as the correct place to customize entities is via the entities page.

You can still use the VSCode editor to edit customize