Have an option to make failed builds/tests emails be set with a "high priority" flag

We use Outlook for email, and it's nice to be able to have the email that comes in with the high priority flag set on when a build/test fails. However, I'd recommend making this a global option that only the admin can change for the whole site.

(If I'm not mistaken there's a X-Priority in the header that can be setup.)

Thanks