[stable22] Add support for different encodings

[backportbot-nextcloud]

⚠️ This backport had conflicts and is incomplete ⚠️

backport of #2385

[blizzz]

backport is incomplete

[Raudius]

@juliushaertl
Had to use a different implementation for this (and stable23) backport.

We changed the way we fetch the file for 24 (for the file locking?) and it is done as part of the create call but I also noticed that the SyncService in 24 still performs the fetch call. So maybe we need to implement something similar to this there as well?

[juliusknorr]

Not from locking but #2225

I didn't remember that the fetch call was still in use in some places, but yes then we should probably forward-port the fetch part also to stable24 and master

[mejo-]

/rebase