[web] Polishing: Simplify Filetype Filter

[tbsbdr]

The filetype filter should receive some simplifications:

1. Media type -> Rename to Type
2. no search within the filter
3. no type "file" - I think this is quite rare that someone searches so generically (it's still useful to have it on the API level, e.g. for dynamic views based on search results)
4. folder as 2nd to last, I think it is also quite rare, but it is quite good if you can search for it

Please track times

Implementation detail:

• the type "file" should not get announced via capabilities

Current

Suggestion

[lookacat]

Should be done by https://github.com/owncloud/ocis/pull/7772/files