Make Qt 3D Studio 2.2 snapshots visible in online staging and production servers

Make Qt 3D Studio 2.2 snapshots visible under preview section of the production online installer. Note that the installer must install this version to 2.2-snapshot etc. folder to avoid clash with older versions. One selected snapshot at a time is visible from online installer. Staging server should always have the latest snapshot available for internal testing, if this is feasible.