generate_key: Move code into main(), follow pylint
generate_key: Move code into main(), follow pylint

So that you can safely import this module without executing a bunch of
stuff, move the generation code into main(), executing it only when the
module is called directly.

global-humanitarians-unite/ghu,global-humanitarians-unite/ghu,global-humanitarians-unite/ghu,global-humanitarians-unite/ghu