Tag based folder view

## Is your feature request related to a problem?
I can tag documents and search using that tag, but I still have to create a folder structure to organize my files.

## Describe the solution you'd like
I'd like to have a custom folder view, next to tiles and list, based on the tags I attach to files.

Imagine a shared space in OCIS where all files are saved in a single directory. All files have no, one or multiple tags attached to it. I want to select "tag view" which shows all the files grouped by tag. If files have multiple tags, they show up multiple times. Files without tags are grouped into the "no tag" category.
It would be handy to have a list of all available tags but as tags are site-wide this might become not desirable.

Alternatively: implement a "custom view" system based on search queries. When I search for all files with tags "tag:invoice + tag:2024", I can then save that query as a view.

My current workaround (which works for web only):
- space called "documents"
- all documents in subfolder "docs"
- create shortcuts with the url to the tag-based search result for each tag
result: when opening the space, a list of urls is visible. opening one of the urls shows the relevant documents, a poor-mans-custom-view-system.