Allow selecting tagged files for copying, moving, deleting, etc.

[bjoern-tantau]

Is your feature request related to a problem? Please describe.

My wife wanted to find some photos she made. I found them and tagged them one by one. I thought this way she would be able to see them on her phone, but the Android app doesn't support tags yet (reported in nextcloud/android#548).
So I wanted to at least collect all the photos in a common folder or just download and send them. But it is not possible to select files in the tagged files view to move or download them all at once.

Describe the solution you'd like

I would like to perform the same file operations in the tagged files view as when browsing by folder.

Describe alternatives you've considered

Well, I'll just go ahead and download them all individually and send them by mail or Signal. Or I could try to get her to use the web interface to see the photos.

[earendil1]

Is your feature request related to a problem? Please describe.
I have thousands of files which are to be tagged in order to be managed: languge-english, status-bilingual, work-revision-todo, priority-high, priority-low etc. There are several dozen files sharing the same tag and filtering using several tags would allow to select the results in order to perform group actions on them (tag them with a specific project tag, assign them all to a deck project, share them all with a collaborator, etc.)

Currently only the tag results are able to show results of same-tag files across all directories The global search does show result previews (on the right as a list) for subdirectories but actions can be performed only on the results in the current directory (Application view window in the middle). Both for tag results and for global search it would be useful to able to perform actions on the groups of results, not only on each single file.

Describe the solution you'd like

So it would be nice to be able to perform operations with the files filtered by tags by groups or selections of files.

Describe alternatives you've considered

Perform actions on single files.

[peter-neumann-dev]

Would be nice to have it +1