Support Request feature improvement

JIRA Support Request feature could be improved to be of more immediate use for support and internal systems.

For more information on the issues with this feature and proposed solution see the INSTDATA project.

For this iteration I would like to ask only for two simple improvements:

1. add a unique header parameter to the existing message that we could use to uniquely identify these requests in the support mailbox. E.g. X-JIRA-Support-Request-Version=1.0 or something along those lines.
2. attach the collected properties to the message in a machine readable form. I.e. properties.store() should even do at this stage. Attaching the properties to the message will avoid them getting mingled with security and copyright warnings, personal signatures and wrapping etc.