Add per-release info to the documentation

[jcfreeman2]

As discussed at this Monday's Coordination Team meeting. Basically, the idea is as follows:
On the main page of the official documentation, right under "DUNE DAQ Software Documentation Home", there'll be a section with a name like "Release Info".

If you click on "Release Info", there will be a table showing the linkages between the detector release and the core release it depends on (e.g., fddaq-v4.4.0 / coredaq-v4.5.0, fddaq-v4.3.0/ dunedaq-v4.4.0, etc.). Furthermore, for future releases there will also be release notes.