Use proper error pages instead of always redirecting

[juliushaertl]

Implements a generic 404 error page instead of always redirecting to the login page or dashboard as discussed in #33048

Can be tested by browsing to an invalid url like /index.php/apps/nonexisting

Added the pending documentation label as we need to adjust the nginx config in the docs accordingly to what was done in the htaccess.

[szaimen]

Does this close nextcloud/android#10628 (comment)?

[juliushaertl]

Does this close nextcloud/android#10628 (comment)?

It would help but doesn't explain why the redirect is happening. The 404 should already be returned by the dav app, so it might just hide another issue. But I cannot reproduce this case either. Maybe it is related to the general webserver configuration (besides .htaccess)?

[CarlSchwan]

😍

Finally the current behavior was driving me insane some times!

[szaimen]

autoloaders not up-to-date

[juliushaertl]

Nginx config does't seem to have this anymore since a long time:

https://github.com/nextcloud/documentation/pull/392/files

Does anyone have a nginx setup at hand to check if this is properly working there?

[DaphneMuller]

hello @juliushaertl ,
Thank you for your work on this pull request! This ticket seems to have the tag 'missing documentation', is there any chance you could clarify what documentation is missing? Is this for admins or for app developers?

[juliushaertl]

Documentation is already up to date, but I've added a note for administrators with steps to take in #34692