* feat(cli): send error notifications and snapshot reports
Notifications will be sent to all configured notification profiles
according to their severity levels.
The following events will trigger notifications:
- Snapshot is created (CLI only, severity >= report)
- Server Maintenance error occurs (CLI, server and UI, severity >= error)
- Any other CLI error occurs (CLI only, severity >= error).
A flag `--no-error-notifications` can be used to disable error notifications.
* added template tests
* improved time formatting in templates
* plumb through notifytemplate.Options
* more testing for formatting options
* fixed default date format to RFC1123
