CW: Add terms of use to export

This MR fixes #1738 (closed), fixes #921 (closed),

Description

By exporting files in a block (e.g. DownloadBlock) with or without License (terms-of-use), the exported files won't get any term-of-use relationships data. However on the other hand upon importing the data, it looks for that relationship attribute and set that if exists. Therefore, the problem occures becasue of the absence of this relationship.

Solution

• Upon exporting fileref data, it checks if that terms-of-use attribute exists in the relationships, and then adds it to the export info (file.json)
• Upon importing and in the createFile method, the checker was faulty, as it assumed that the terms-of-use always exists! So, the solution was to make that checker more accurate there!

added BIEST Komponente: Courseware labels

requested review from @rlucke

assigned to @zamani

changed the description

added 3 commits

• 42900868...b1df2e8c - 2 commits from branch main
• e49fd0a5 - Merge branch 'main' into biest-1738

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mentioned in merge request !1154 (closed)

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merged

mentioned in commit 108f0ee8

mentioned in commit b206cd28

mentioned in commit a6e116ec

mentioned in commit f750add5

mentioned in commit 73da2af1

mentioned in commit hochschule-wismar/stud-ip@86424e64