LDEV-1323 overhaul add/remove user screen which didn't scale well for sysadmins - users added via search field now, with the option to click a link to retrieve all potential users
LDEV-1301: Changing some of the I18N labels for the configuration screen to reuse existing labels. Removed the LearnerProgressBatchSize as we aren't using it for the Learner Progress screen after all.