Add alert that snapshot was successfully removed / created

While testing version 1.0.0, I noticed that if you have a lot of snapshots like 20 and you decide to delete one of them, the snapshot is deleted, but there isn't any alert/notification about it.

In my case, I have:

• Snapshots created by cron
• Pre-update snapshot
• After-update snapshot

I could be sure just by remembering ID which I deleted that it was deleted. Similar experience is when creating snapshot, but that's clear that it was created by checking the latest one there.