Pybombs should request confirmation before installing or removing packages

[dkozel]

Issue moved from the GNU Radio repository to the Pybombs one. https://github.com/gnuradio/gnuradio/issues/1823

@lgommans reported:

It's nice that gnuradio tries to install all required packages without having to look for the package name myself, but I'd rather get a list and get a prompt to confirm. As it is, it had to remove libcurl3 and it just went ahead and did that. I think removing system-wide packages automatically is a bug.

This happened when running pybombs install gnuradio as my local user. Apparently it uses a previous sudo session, so I again had no interaction in which I might have chosen not to allow it.

[lgommans]

Thanks for moving it!