MQTT Manual config items under integration key Fan and Light platform

[jbouwh]

Proposed change

The way manual MQTT items are configured is changing.
The first PR will support configuring manual MQTT Lights and Fans by placing the config under the integration key.

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: Move manual configuration of MQTT fan and light to the integration key core#71676
• 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.

[jbouwh]

@frenck are the page anchors okay the way I used them?

[frenck]

Thanks, @jbouwh 👍