Add documentation for tomorrowio as well as climacell deprecation

[raman325]

Proposed change

Because ClimaCell has rebranded, we are creating a brand new integration and automatically migrating climacell users over to it. Under the hood the code is mostly the same, so the new tomorrowio page is mostly a copy/paste from the climacell docs. I also added a note on the climacell page about deprecation and removed installation instructions since it will no longer be available for setup.

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 tomorrow.io integration to replace Climacell core#68156
• Link to parent pull request in the Brands repository: Add branding for tomorrow.io by symlinking to climacell brands#2742
• 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.

[frenck]

Thanks, @raman325 👍