Proposed change

Add value_template option to KNX expose.

Some typical KNX value ranges don't match with HAs. Eg. a closed cover in KNX is 100% whereas in HA it is 0% or volume (media player) in KNX is 0..100% whereas in HA it is 0..1 (float). With value_template a user can easily bring HA entity states to KNX.

Example configuration:

knx:
  expose:
    - type: percent
      address: "1/1/1"
      entity_id: cover.office
      attribute: current_position
      value_template: "{{ 100 - value }}"
    - type: percent
      address: "2/2/2"
      entity_id: media_player.kitchen
      attribute: volume_level
      value_template: "{{ value * 100 }}"

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: Add value_template option to KNX expose home-assistant.io#32841

Checklist

• The code change is tested and works locally.
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• Tests have been added to verify that the new code works.

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

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