Send Email to Contacts - Use Pre-built Message Templates

Provide users with the option to select a saved message template (from civicrm_msg_template) from a drop-down and then edit the contents in the existing content field(s). The "Select Template" drop-down is only displayed if there are "is_active" rows in the templates table. Ideally, we should use a dojo widget to grab the msg_text from the DB and populate the form

If the user edits the text / html content loaded from the template - we should ideally ask them if they want to save their changes back to to the loaded template OR save as new template OR neither.

NOTE: This issue will need further specification after discussion of how to handle HTML vs. TEXT template formats.