Upgrade to Nextcloud 25.0.0

Upgrade to Nextcloud 25.0.0

Semiautomated major upgrade by means of Docker container management with severe problems, but some manual database updates.
The only minor issue without solution is:

Technical information
=====================
The following list covers which files have failed the integrity check. Please read
the previous linked documentation to learn more about the errors and how to fix
them.

Results
=======
- related_resources
	- EXCEPTION
		- OC\IntegrityCheck\Exceptions\InvalidSignatureException
		- Signature data not found.

Raw output
==========
Array
(
    [related_resources] => Array
        (
            [EXCEPTION] => Array
                (
                    [class] => OC\IntegrityCheck\Exceptions\InvalidSignatureException
                    [message] => Signature data not found.
                )

        )

)

Nextcloud Hub 3
Announcing Nextcloud Hub 3