Admin interface: rename SplashscreenSet to TeaserSet

Conflicts:
	db/personas.data.psql
ui: js: clipboard: don't parseInt() UUIDs

this lead the clipboard to load images such as `/media_resources/NaN/images` (if UUID starts with character, doesn't work at all);
and `/media_resources/2/images` – using just the first numbers of a UUID, which led to "not authorised" flashes (even worse)
ui: set: resources view: js: when saving the display setting, reset query params
Fix: admin migration exception  where there is no (old) admin group
Rename MetaDepartment to InstitutionalGroup

Conflicts:
	db/personas.20140721075032.data.psql
	db/personas.20140808090502.data.psql
	db/structure.sql
	features/admin_groups.feature