Import a meeting with files didn't work #3940
Description
Describe the bug
Meetings with files can be exported but not re-imported, as the files no longer exist and this leads to errors.
Note: This function is only available to superadmins.
How to Reproduce
Reproduction will be added after general discussion of the topic.
Expected behavior
Best solution would be, that meetings can be exported and imported with files. From a practical point of view, this is urgently needed, as missing files can lead to various problems. Example: A meeting has stored a font, set all formatting to it and is exported. The expectation is that this will work after the import. Losing the file relation would be quite bad.
Additional context
The issue initially serves as a basis for discussion.