add update_system method to api class
renamed basic_auth to system_auth
test for Clinet.update_system()
add update_system() to the yast layer
update system automatically on product activations
make rubocop happy
Merge pull request #137 from SUSE/review_140711_add_support_for_updating_hardware_info

[Review] Request from 'digitaltom' @ 'SUSE/connect/review_140711_add_support_for_updating_hardware_info'