Improve Display configuration

This makes display arrangement and single display mode work, also rotation and scaling.

TODO (mostly mechanical now):

• bring back make/model/serial - v2 of output-mgmt supports it~ (allows fancier names)
• fix rotation direction
• fix g-c-c being out of sync after config update
• use zwlr_output_configuration_v1_test in phosh_monitor_manager_apply_monitor_config to test config (can be follow up, phoc doesn't handle it anyway atm, lets fix phoc side first)
• allow to set mode (can be follow up)
• fix mirroring (can be follow up)

Closes: #416 (closed), #138 (closed), #140 (closed), #436 (closed)