Fix #204, Doxygen frontpage refactor and cleanup

[skliper]

Checklist (Please check before submitting)

• [x] I reviewed the Contributing Guide.
• [x] I signed and emailed the appropriate Contributor License agreement to GSFC-SoftwareRelease@mail.nasa.gov and copied cfs-program@lists.nasa.gov.

Describe the contribution

• Fix #204

Testing performed Documentation change only, but still built and ran unit tests

Expected behavior changes None

System(s) tested on

• Hardware: i5/wsl
• OS: Ubuntu 18.04
• Versions: Bundle main + this commit

Additional context None

Third party code None

Contributor Info - All information REQUIRED for consideration of pull request Jacob Hageman - NASA/GSFC

[astrogeco]

CCB:2022-03-23 APPROVED