Automatically notify app admins on simulation failures

[hdoupe]

Currently apps have three roles:

• read
• write
• admin

I think we should notify either those with write access or those with admin access if there is a validation or model run failure. I'm leaning towards notifying all admins of the app. They could then choose to forward the email on to other people who need access to the error message.

For now, I will manually forward the error emails added in #370 to the relevant maintainer(s) on failures.