allow deletion without using TUI

Problem It would be nice to be able to use npkill without using the TUI as it is a potential extra step/click/key and a slight(:-P) performance impediment.

Solution Add a command line argument that skips the UI, runs npkill deletion service, and displays results on command line.

Alternative The best set of arguments I have found thus far is npx npkill -D -x -y -nu which deletes node_modules, skips hidden stuff, auto-confirms, doesn't check for updates, but still requires an exit of the TUI.