[Feature] Partner-sharing but only with specific tag(s).

The feature Now that we have "show in timeline" option in Sharing settings, it is even more important to have tags implemented. Say, I set a tag called "private" and then set my sharing settings as "All except 'private'", then, all matching photos I take can be viewed by other people when they view my timeline, or have my photos shown in theirs. Of course, tags are already a much requested feature, but the current boolean choice of sharing _all_ photos or _none_ of them makes it hard to automatically have a combined family album thing going, since you might take some photos you don't wanna keep private but not archived. This is similar to but not identical to #2451. Also, tags have been requested in #1651, #3518 and others. This is merely a use-case, albeit an important one, for tags. TLDR is that adding proper tagging support would enable easier implementation of so many QoL features. Platform • Server • Web …