Remaining doc HTML style issues

[wmamills]

The following style issues should be addressed at some point.

• Add hover feedback to the logo like in Sphinx to let the user know it is a link
• Try harder to move the Doxygen "Back to OpenAMP" link above the library name line (in nav bar)
• Make the layouts match exactly between Sphinx and Doxygen
  • Nav bar header section size and layout width
  • Content pane fixed width and justification
• Sphinx content does not honor system level light/dark preference and does not have a light/dark switcher
• Refactor our css to put all the colors in one file and then use them in Sphinx and Doxygen specific css files
• Have a pro designer tweak our colors
  • Colors used on page should blend better with Nav bar theme
  • Colors for Sphinx TOC highlights should be more subtle
  • Pick all colors with a designer's eye

[wmamills]

Fixed the Doxygen version name in a new commit for PR#26

[sipke]

This looks like it may have been addressed already?

[arnopo]

@wmamills : Any remains concern that as not been addressed