Remove reference to OMERO_HOME

Usage of $OMERO_HOME is not recommended - see:
- https://trac.openmicroscopy.org.uk/ome/ticket/10603
- https://github.com/openmicroscopy/ome-documentation/pull/320
Detail distributions descriptions
Fix fields grouping for insight input validation

Enables OMERO.insight to disable the "run script"
button on invalid (empty/non numeric) input.
Harmonize fields grouping numbering
Simplify fields descriptions
Add type hint for IDs list
Add link to scripting style guide documentation
Rename display label for 'annotated_data_type'

For readability and automatic fields sorting
by name in OMERO.web.
 Update user manual screenshot
Americanize spelling
Add missing include/exlude patterns
Add build targets for docs/examples distributions
Add distribution packages description and link
Add changelog
Version freeze from 0.2.2-SNAPSHOT to 0.2.2
Prepare for next development version 0.2.3-SNAPSHOT