Add system information to notification emails

The idea is to add the following system information to all notifications emails, doesn't have to be prominent, but at least it enables you to differentiate them.

Subscription: xyz
Data center: lon09
Munchkin ID: 123-ABC-456

If you are admin for multiple instances it is currently a nightmare always having to guess where this or that error took place. Also, user invitations - people can not differentiate if they are activating sandbox or production (we're on SSO, so the login IDs are the same across systems).