To customise content of the release page notification template, read this - Customising release notes content

To add the release page notification action in a rule, read this - Actions

To configure your own address (only available in the Cloud version) for sending out emails, read this - Setting up SMTP (to send emails via your company domain)

For all practical purposes, this type of template is exactly the same as that of an email template. Thus, all the functionality remains as explained here.