Add dropdown to switch teams for issues

[delaurentis]

Switching the owner of an issue within the same team currently works well, but two use cases don't:

• Moving it as an unassigned item to a different team (important so they can find their own owner)
• Moving it to another team member (since we don't show a list for / can't search for people in all teams)

[delaurentis]

Updated to allow switching of project for tickets. If you use 1 team per project, then this is an effective solution. If not, we may still want to implement some team switching or alternate names in the assignee popup.