When moving to argparse, the common set of options (--noinput,

--debug, etc.) were no longer able to be provided after the

subcommand. That is, rb-site install --noinput no longer worked.
This change addresses that by moving those options into a common

argparser and setting that as a "parent" for all others. This allows

them to all share the same set of options, allowing placement either

before or after the subcommand.
There's also a small tweak to one of the options, which had a wrong

description.

Tested rb-site install and rb-site upgrade with common options

both before and after the subcommand, and verified they worked in

both cases.