fix #11446: add robot framework scripts for testing the Insight data browser

`./build.py -f components/tests/ui/build.xml ui-test-insight -DTEST=thumbnails` should run fine, with `components/tests/ui/target/reports/insight/thumbnails/report.html` being all green passes.

Fixes https://trac.openmicroscopy.org.uk/ome/ticket/11446.