[WIP] Redesign hastemplate field to behave like deepcat
Bug: T190140
Make the template tags/pills clickable, color the non-existent templates in red, the rest - in blue.
Current problem: clicking on the template name destroys the pill field and turns it into plain text.
Change-Id: I68cdb24d85f6a3f1441bc1d764550b6245761d6b