Add update notifications for LinuxGSM and game servers

[Tank-Missile]

If configured, when LinuxGSM or a game server needs to be updated, send a notification/email or other custom method. Also, if configured, send a notification/email after LinuxGSM or a game server has been updated. Finally, if configured, if LinuxGSM or any game server fails to update, send a notification/email. The notifications/emails sent could be customized depending on the information you want. Would you prefer simple messages such as "Server 1 has successfully updated and restarted!", or perhaps you want the entire update log included? What if the server successfully updates but fails to start? There are many different scenarios that could effect the emails/notifications sent.

[request-info]

The maintainers of this repository would appreciate it if you could provide more information.

[avsaponchik]

from what i get he means that:

1. linuxgsm gets updated
2. game server gets updated
3. notification send to email that update was successfully installed (or not)

[Tank-Missile]

That could also be an option, but what I really want is to receive notifications when updates are available to LinuxGSM and game servers. This is so I can manually update LinuxGSM or my game servers myself more easily. I rather not have LinuxGSM automatically update on a timer.

[dgibbs64]

relates to #2001