[otacke]

When merged in, will:

• Add support for migrating H5P.ThreeImage (regular Virtual Tour content) alongside the existing migration for H5P.NDLAThreeImage (NDLA's version of Virtual Tour)
• Fix hotspot positions for H5P.NDLAThreeImage content (same as Fix Hotspot interaction positions #3300 would, that request could be closed)
• Fix default translations that were not set before when migrating content in contrast to how H5P's upgrade scripts would handle it for regular content upgrades

Changes in code:

• The AdminContentMigrateController will now look for both, the regular Virtual Tour and the NDLA Virtual Tour. Changed fromLibrary to fromLibraries to make that clear and then just picked the data by id and changed places in the code where needed.
• I uncommented the code in alterParemeters that was copied from VT2ER but not used (as it was only relevant for the regular Virtual Tour) and put the existing part into a migrateScenes function.
• I added the fixHotspotInteractionPositions function that was added to VT2ER recently for NDLA Virtual Tour, called in alterParameters
• I also added l10nDefaults that had been neglected before, to set default language strings (as VT2ER would, as it is common practice to do that in H5P content type upgrade scripts).
• The blade template was adjusted to deal with NDLA's Virtual Tour and the regular Virtual Tour.