A new option has been added for configuration of SMTP timeout:
- notifications.smtp-timeout

During tests, we can change this timeout to be small, so we aren't
depending on hardware-based RNG to pass the timeout.

Without a timeout, users can run into a long-running test for no
particular reason.
Signed-off-by: Kevin Morris <kevr@0cost.org>

- Removed notify sharness test
Signed-off-by: Kevin Morris <kevr@0cost.org>