Discard ignored files

**Is your feature request related to a problem? Please describe.**
I need to ensure clean build, sometimes ignored files are the problem and need to be purged.

**Describe the solution you'd like**
Two alternative solutions:
* Modify "Nuke working tree" menu item to do `git -fdx` instead. (I'm not 100% sure it's semantically correct)
* Add option "Discard ignored files" to run `git -fdX`

**Describe alternatives you've considered**
Doing a custom command, but there's a chance that I'll forget about it, and I don't believe I can add it to the delete menu itself.

I could probably do the work myself, but I need guidance from maintainers to what option they would deem acceptable.