closes https://github.com/TryGhost/Ghost/issues/8540
- use `{{vertical-collection}}` in the tags dropdown filter list, opening the dropdown is now virtually instant as it's not attempting to immediately render components for every tag in the list
- remove pagination/infinite scroll from tags screen
- load all tags when accessing the tags screen
- will pause to show spinner if no tags have previously been loaded
- if tags exist in the ember data store, show the list immediately and load/update list in the background
- use `{{vertical-collection}}` to render enough tags to fill the scrollable area with a small buffer and use occlusion and element re-use to swap tags in whilst scrolling (suuuuper fast no matter number of tags loaded)
- scroll tags into view when they are selected (keyboard nav now makes a lot more sense)
- tested with 875 tags and 2x/5x CPU throttling with no major slowdowns 🎉
d65666f90b