blitz: Split RObject out of RTypes
Concurrent loading of PIXELDATA EventLogs (Fix #12526)

The EventLogQueue was not intended to have simultaneous
threads loading logs. Instead, we now load a group of logs
in bulk and then schedule these for background processing.

The current pixel id is immediately incremented to after
the set of logs even before processing begins. Since there
was previously no transactional guarantee that a pyramid
must be created before moving on, there is no regression.
Instead, further clicks (i.e. thumbnail requests, etc.)
will have to generate a new PIXELDATA log as before if
a pyramid-creation has failed.
Make PixelData EventLogLoader configurable
Change LockTimeouts to WARN
Clarify numThreads in PixelDataThread
More javadoc and minor cleanups
refactoring settings.py

 - adding documentation
 - reordering and grouping
removing space, causing: Inline literal start-string without end-string
FindIce: Remove unneeded search path modification
Merge pull request #3011 from rleigh-dundee/cmake-groups

OmeroCpp: Group code into folders
FindIce: Respect Ice_FIND_QUIETLY when printing messages
merge develop -Dorg -Ijburel/openmicroscopy:qa-submit-new -Ssuccess-only: PR 2835 (Update OmeroPy/src/path.py)
merge develop -Dorg -Ijburel/openmicroscopy:qa-submit-new -Ssuccess-only: PR 2895 (Reload groups after users added/removed)
merge develop -Dorg -Ijburel/openmicroscopy:qa-submit-new -Ssuccess-only: PR 2926 (OmeroCpp: Glob test sources)
merge develop -Dorg -Ijburel/openmicroscopy:qa-submit-new -Ssuccess-only: PR 2927 (OmeroCpp: Glob example sources)
merge develop -Dorg -Ijburel/openmicroscopy:qa-submit-new -Ssuccess-only: PR 2965 (blitz: Split RObject out of RTypes)
merge develop -Dorg -Ijburel/openmicroscopy:qa-submit-new -Ssuccess-only: PR 2970 (Bugfixes for 5 0 4)
merge develop -Dorg -Ijburel/openmicroscopy:qa-submit-new -Ssuccess-only: PR 2979 (Thumbnail cache busting)
merge develop -Dorg -Ijburel/openmicroscopy:qa-submit-new -Ssuccess-only: PR 2982 (Fix #12530: detect Windows if closing RFS.)
merge develop -Dorg -Ijburel/openmicroscopy:qa-submit-new -Ssuccess-only: PR 2994 (Ensure that identity request variables are UTF-8 encoded)