Issue 564: Refactor navigation on cluster installation pages

[joewxboy]

Pull Request Template

Description

Updated the last modified headers on the changed pages. Added navigation links to the appropriate pages. Did NOT divide installing the cluster agent sections into separate pages. Will instead put behind tabbed navigation on a single page when we migrate to Docusaurus. Just The Docs does not have this type of navigation widget.

Fixes #564

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• This change requires a documentation update

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Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings
• I have tagged the reviewers in a comment below incase my pull request is ready for a review
• I have signed the commit message to agree to Developer Certificate of Origin (DCO) (to certify that you wrote or otherwise have the right to submit your contribution to the project.) by adding "--signoff" to my git commit command.