Improve feedback in 'Instance Crashed' email

[knolleary]

The email sent when an instance has crashed is extremely minimal and doesn't provide much help to the user as to what to do next, other than look at the logs.

It would be better to provide some more context to help the user decide what to do next.

The email is triggered by the launcher posting an audit-log entry following the abnormal exit of the NR process. If the launcher can provide some more information in that audit log entry we will be able to show that in the audit log as well as in the email.

Some initial thoughts/questions/things to investigate

1. Can the launcher tell the difference between 'killed due to memory' and 'uncaught exception' - the two most likely causes. If so, tailor the message accordingly.
2. Include a snippet of the logs preceding the exit. If there's an uncaught exception, we should be able to parse that out. It may be trickier to include the logs in the email and get the formatting right.
3. Depending on any insight we can infer from the logs, include recommended actions in the email.

The email should also include the team name to provide more context for what instance has crashed.