Adv gen config

This branch has been waiting on, cleans up and finalizes work from:
 * gh-2652 - reviewing etc/omero.properties
 * gh-2639 - event log queue work on search & metrics
 * gh-2595 - auto-memory configuration
 * gh-2581 - initial metrics PR

The main goal is to generalize the `omero.mem` functionality so that other properties like those for the metrics system can vary between JVMs. (See https://github.com/joshmoore/openmicroscopy/commit/938ca10458b7f2ecc34596826f64caed86c95bf8 for an example). In addition, a parser has been written (`etc/glossary.py`) which parses `etc/omero.properties` into RST for inclusion in the documentation (/cc @kennethgillen) The entire file should be made more readable in the process.

 * [x] Parser for `etc/omero.properties` (/cc @sbesson)
 * [x] Generation of properties (/cc @sbesson, @manics, @kennethgillen)
 * [ ] Rename properties from `omero.mem` to `omero.jvm(cfg?)`
 * [ ] Rename `bin/omero admin memory` method
 * [ ] Move `etc/glossary.py` to a better location.

Once the above steps are all complete, this will primarily be tested for functionality by the daily deploy jobs. Feedback is encouraged for the naming of properties and general usability of this generated configuration idea.