Tag fetching and searchable tags, but overrides existing list of tags

[James-Cocker]

Why?

Solves #2466 by extending functionality of editing tags to be a filterable, selectable list of tags where you can query existing tag objects.

[jadecarino]

@James-Cocker Hi James, from my testing mostly looks good but there's still some funny behaviour with the sorting. Here's how to recreate:

1. Go to a test run with no runs
2. Add the tags 'artifact' and 'http' from the dropdown
3. Add a tag 'jade' (after http alphabetically) and it appears in the correct alphabetical order (artifact, http, jade)
4. Then unselect 'http' as a tag and the order will put 'http' at the bottom of the list

Is this the intended behaviour? I've been playing around and it seems to be some inconsistencies between sometimes the ticked tags group together and then the unticked tags group together, and each group is alphabetically sorted, and then sometimes alternatively the whole tags list both ticked and unticked are combined and sorted alphabetically as a whole. Whatever behaviour you decide upon should stay consistent I believe.