DEV: Separate Runner Gateway Functionality from Device Cloud Functionality

These scripts constitute the best configuration for GitLab Runner Gateway devices that may or may not need to be part of an orchestrated device cloud.

I would like to separate the Runner Gateway registration code to be called by the Device Cloud code so that the Runner Gateway can continue to show the best configuration and be used independently.

At the same time, this code should be maintained with and always be compatible with the device cloud which has driven the development of the best configuration for Runner Hardware Gateways.