Allow adding custom fonts to the buil-in server

[elpraga]

I believe that being able to add additional fonts to the built-in server would greatly improve it's usability when simultaneous editing a large number of documents is not required, but using specific fonts is.

[timar]

The built-in server can read system fonts. There is a problem with nextcloud-snap though. See https://github.com/nextcloud/nextcloud-snap/issues/1628

[elpraga]

Ahh, I did not know that!

Trial you for the update!

[Steffen75]

I'm seeing a problem right now that could be somehow related. But my server is running on Debian 10 using the built-in CODE. Right now I only get Carlito as a font. Sometimes when I'm lucky I get all installed fonts but that's only in the writer part of CODE.

[mermaid-marina]

My built-in server can read system fonts. But after I have copied new fonts to /usr/share/fonts and did "sudo fc-cache" (and "sudo systemctl reload apache2"), they didn't appeared in CollaboraOnline. I had to reboot the root server to make them appear in Collabora. Is there a way to use new installed fonts in CollaboraOnline without rebooting the server?

[Update: Found out - had to do restart apache2 instead of reload. Should have known that...]