Use EntityReference to select a email template, more convenient with long lists
In the Send Email Action Form, a template must be selected. This list can be long (and often the templates have the same start, which makes it even more cumbersome. This PR replaces the select box with an ajax entity reference select, where typing a part of the template name gets it selected.
Before
After
The actions need a template select, so it replaced in all three of them.