Allow send email/execute program when errors

[simonbcn]

Suggestion

Currently qBittorrent allows you to send an email/run a program when a torrent has been downloaded or run a program when a torrent is added.
But it does not allow to do the same when an error occurs: disk full, error in a torrent (of whatever type), missing files, etc. when I think this is a really useful use of notifications, especially when running without GUI.

Use case

No response

Extra info/examples/attachments

No response

[RivenSkaye]

@luzpaz may I ask why you're posting on 11 issues (so far anyway) that they're supposedly related when some of them are different problems entirely?
For example:

• Existing configuration file gets corrupted if there is no free disk space available #14523 which is about a circumstance in which a succesfully completed download fails to run the specified command.
• Run external program on torrent completion is not working #17839 is about qBT failing to run a bash script (issue might even be as simple as bash not being on their %PATH%, reading through the thread)
• Run external program once torrent completes for RSS Downloader Rules #4820 is about RSS downloads not triggering a command (on successful completion)

None of those are related to running a command or sending an email upon an error and I didn't even check the other issues you commented on

[luzpaz]

Sorry, I had too many open tabs while trying to triage. I must of missed the email portion on this ticket and thought it was a generic state change that would trigger an external app.