Better galllery

[s314cy]

A great addition would be a gallery page containing photos hosted on the CLIC Nextcloud, with subpages corresponding to folders on NC. Ideally, the display would resemble https://polylan.ch/website/photos/

Following this idea, all the website's images could be moved to Nextcloud instead of storing everything on Github.

[codeofmochi]

See #71 if that's relevant. Although I guess nextcloud may also have widgets similar to the calendar used at https://clic.epfl.ch/events