docs: Provide icons meta-data list.

[tomheller]

Pull Request

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Hi, thank you for contributing to Barista with this pull request (PR).

To ensure a fast process and merging of your PR please make sure it fulfills the
coding standards and contribution guidelines.

• A feature proposal has been provided, discussed and approved first.
• There is a meaningful description of the issue in GitHub (Screenshots are
  often helpful).
• If the PR introduces breaking-changes or deprecations it matches the following
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  • Tests for the changes have been added (for bug fixes / features).
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Please choose the type appropriate for the changes below:

Type of PR

Checklist

• I have read the CONTRIBUTING doc and I follow the PR guidelines
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)