Adapt documentation of kostal plenticore to match changes in core.

[stegm]

Proposed change

PR home-assistant/core#103802 introduces some new sensors from the underlying library. These sensors are important for the energy dashboard. This PR adds the sensors to the documentation and also shows how to configure the energy dashboard with the integration.

Type of change

• Spelling, grammar or other readability improvements (current branch).
• Adjusted missing or incorrect information in the current documentation (current branch).
• Added documentation for a new integration I'm adding to Home Assistant (next branch).
  • I've opened up a PR to add logo's and icons in Brands repository.
• Added documentation for a new feature I'm adding to Home Assistant (next branch).
• Removed stale or deprecated documentation.

Additional information

• Link to parent pull request in the codebase: Add new sensors of Kostal Plenticore integration core#103802
• Link to parent pull request in the Brands repository:
• This PR fixes or closes issue: fixes #

Checklist

• This PR uses the correct branch, based on one of the following:
  • I made a change to the existing documentation and used the current branch.
  • I made a change that is related to an upcoming version of Home Assistant and used the next branch.
• The documentation follows the Home Assistant documentation standards.

[c0ffeeca7]

Thank you, @stegm 👍