Show pruned packages at update and uninstall

[christophenne]

Is your feature request related to a problem? Please describe.
During every update or uninstall its possible that required packages are going to be uninstalled as well. The user does not see which packages are going to be removed at all.

Describe the solution you'd like
UI and CLI should list the pruned packages to the user.

On the UI we currently have the browser-built-in confirmation, this will have to be changed to the same bootstrap modal as in installation and update.

Describe alternatives you've considered

Additional context