Avoid loading anything else than core scripts/styles on empty/base renderAs tempalte

[juliusknorr]

This PR will remove anything but the core js bundle from the base or empty template rendering. This is basically what is described in #10142

The existing RENDER_AS_BASE should be sufficient for this already and seems to be only used in Collabora/ONLYOFFICE these days anyways (as far as my git checkouts showed). We could even discuss if dropping the server.scss might be a good idea and instead just load the css variables.

Things kept:

• Core js bundle
• Server styles
• CSS variables
• Translations

Since this may be a breaking change, this should be added to the developer docs after merge.

[skjnldsv]

This will also be usefulfor the pdfviewer iirc. This is what we discussed last year, isn't it?
nextcloud/files_pdfviewer#202

[skjnldsv]

Also, does it make sense to introduce a new render constant like RENDER_AS_CLEAN ?

[juliusknorr]

I don't see a reason to introduce yet another one if we manage to clean up what is being loaded in RENDER_AS_BASE. Though if you see any use case of having two separate ones, we could add that of course.

[skjnldsv]

Nope, all good for me @juliushaertl 🚀

[PVince81]

revive for 25 ?

[juliusknorr]

After having another look I'll double check what the existing ones in RENDER_AS_BASE actually do and also try to document this for the other types based on the current behaviour.

[juliusknorr]

We switched to a different approach for Collabora now which does not require us to do another template rendering, so I'll close this due to lack of time to finish. Anyone is welcome to pick this up of course if needed.