Demo accounts, protected downloads and prominent dataset Beta labels

Adds a Demo account role to user creation and editing, allowing tool testing with individual account storage.
Denies mission exports, WebODM Plugin, RC2 Transfer and release downloads for Demo accounts, including direct URLs and existing download permissions.
Routes static RC2 archive URLs through authentication and download authorization.
Displays localized Demo guidance and removes active download actions for Demo users.
Moves RC2 Transfer after the WebODM tools in Modules and Support.
Shows prominent Beta badges for affected sources in Update Service 1.1.12, installation administration, Geozone status and source details.

Changelog