Adding Panasonic Viera remote documentation

[joogps]

Proposed change

This pull request adds some information about the new remote platform being added to the Panasonic Viera integration documentation page. I was also thinking of writing a section about how to deal with the "Couldn't gather device info" error (check this answer for details), but I'm not really sure if that's really essential.

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 remote control platform to Panasonic Viera core#42450
• Link to parent pull request in the Brands repository:
• This PR fixes or closes issue:

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.

[joogps]

uh...

[frenck]

Thanks, @joogps 👍