Enable Customized Email Notifications

[#1]

As a System Administrator I would like to have access to customize any/all of the email notifications that are enabled. For example, if I activate the 'Issue Add to Issue Primary Contact' event notification I would like to be able to edit the text in the email that is sent to the Primary Contact. This will make all email/event notifications more use and provide the content the receiver requires.

[#2]

We would also like to see the ability to customize Email Notifications including to choose custom form data and have this inserted into the subject or body fields.