omero: Add detailed version requirements

Conversion of https://docs.google.com/spreadsheets/d/1TRJUhdMZ_pnHxg1TUk9Lf_oQcx2paZtwWMjTybQ7qZo/edit#gid=0 to sphinx markup

This isn't intended to mirror the installation prerequisites; it's primarily of interest to ourselves and sysadmins who need to know what's supported for the deployment timeframe of an OMERO installation.  From that point of view it's a much more detailed overview of each prerequisite, which could be cross-referenced from the install docs.  This is a detailed list of all of the released versions of our prerequisites, and their release and support timeframes.  It also details which versions are provided by each version of each distribution/operating system.  The intent is that this gives a detailed overview of what's supportable, and what's obsolete/unsupportable, and the varying degrees between these states, to enable us to clearly plan what we will support for the 5.1 (and later) releases.  The support states are certainly something which needs wider discussion; this is just the initial conversion of the spreadsheet to give us a starting point for doing that (I just filled in vaguely sensible values to mostly match the current status quo).

This might not be in the most appropriate place in the manual, it can certainly be moved to e.g. the developer part if that's better.  While it's not intended to mirror the installation instructions, it's clearly got some similarities, so if there's a way to better integrate the information here with what's already in the manuals, 

I've checked the HTML and PDF tables, but they could do with double-checking to ensure they are legible.