Different Exit Codes depending on exit situation

[xeruf]

I would like to have different exit codes for situations such as:

• completed, but with failed steps
• interrupted (quit)
• unexpected exit

Because when topgrade was quit manually, I don't want to run any subsequent commands in my script.

Also, when I quite topgrade running on a remote machine, it continues running locally, which can be quite annoying - using the exit code it could itself handle that case, too ;)