Describe the bug

tests/orphaned-content.py isn't actually discovering all files that are unlinked or mislinked across the repository, and isn't ensuring that the TOCs are including all files in the repository.

To Reproduce

1. Run python tests/orphaned-content.py
2. See only single result that hasn't been addressed: ./src/deployment-guides/img/tpsm-ag-on-vsphere/new-project-sup-svcs.png
3. Try a simple grep to see whether any document references some files:
   • find src/ -name 'tpsm-ag-on-vsphere-dep.md' && grep -irsn 'tpsm-ag-on-vsphere-dep.md' src/
   • find src/ -name 'tap-on-tkgi.md' && grep -irsn 'tap-on-tkgi.md' src/
   • find src/ -name 'tko-data-protection.md' && grep -irsn 'tko-data-protection.md' src/
   • etc.
4. See that the files, though they indeed exist, aren't being linked to from anywhere else

Expected behavior

That all these files should be failing the tests/orphaned-content.py tests.

Not only that, but this repo claims a TOC at src/toc.md. Many of the files throughout the repository are not listed in this TOC, and it appears that their are many other TOC files (./src/toc-air-gap.md, ./src/toc-edge.md, etc.).

If you combine all the links within this TOC files, there still are several files that aren't linked to from any of these TOCs. Missing links to non-TOC MD files should be surfaced. If the repo is meant to be used differently, and these TOCs aren't meant to function as I believe they do, than the repo documentation should be expanded to help reflect this.