[Docs RFC]Clean out the unused metadata files from the doc navigation files.

[billy-the-fish]

Describe change in content, appearance, or functionality

[Provide as much detail as you can]

Subject matter expert (SME)

[If known, who is a good person to ask about this topic]

Deadline

[When does this need to be addressed]

Any further info

[Anything else you want to add, or further links]

Contributing to documentation

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• For information about how to suggest a change, see the contributing guide in our GitHub repository.
• For information on style and word usage, see the style guide