Ability to remove sandboxes

[gelatinbomb]

Description

First of all I want to thank you for the project. It's super useful and I think it has potential to be at least a close alternative to Sandboxie.
It should be simple since I found you can delete by removing all the files related to the sandbox in the .local folder. It would be quicker to have a button on the UI.

[igo95862]

Hello,

Yes you can delete sandbox by removing the instance folder.

rm -r ~/.local/share/bubblejail/instances/instance

I thought about having a CLI command but decided against it for now. Running rm is too destructive if user runs it on accident. The XDG trash is a way to make it less destructive but the current python-xdg library does not support it.

It would be quicker to have a button on the UI.

GUI needs a rework before that.