Feature Request: Drag notes onto a tag to assign those notes to a tag

### What
It would be nice if it was possible to select one or more notes and then drag them to the tags list. If you let them go on a tag it should assign those notes to that tag

### Why
I sort of figured that it already would do this, and tried to do it the other day but it didn't work. At this time there isn't a convenient way to tag multiple notes at one time, and this would allow for that.

Start by locating the macOS views or entry points for note selection and the tags list, then trace how notes are currently assigned to tags. Done means selecting one or more notes, dragging them onto a tag, and confirming that every selected note receives that tag.

Written by the indexing model from the issue text.