Improve DSC Module deployment/updates

[leshkinski]

The DSC Module package management on Pull server (rsPlatform) uses a process within its local DSC configuration to download and deploy the DSC Modules, which is incorrect...

A more reliable way would be to implement a process outside the DSC configuration, which checks its configuration frequently and loads the modules as required. Pull server DSC configuration should be used to deploy and maintain the required configuration to support this process, but not be an active part of it.

This would be similar to how client registration/re-registration is now handled - outside of the DSC configuration itself.