fixes #11170 - pass quoted args through foreman-rake

Use the special "$@" to correctly pass quoted arguments through
foreman-rake, through su and to the underlying rake command. Ensures
the JSON in this command is unharmed:

foreman-rake config -- -k trusted_puppetmaster_hosts -v '["foo.bar.com"]'...

Fixes #9751: Correct examples for rake config usage.

Refs #3809 - Remove cops for empty lines

Refs #4611 - rake-ify foreman-config and db_pending_migration/seed in settings

This way, we can determine in the installer if the rake
db:migrate/seed should be run in the installer.

Later, we also could use this information to inform the entering user
that the application is not in ready state yet: preparation for...