Create temp folder for resources to use and clean up afterwards

[SteveL-MSFT]

Summary of the new feature / enhancement

Similar to how Pester provides a testdrive to tests that get cleaned up afterwards, it may be useful to provide a temp location for resources which get cleaned up once dsc is completed execution

Proposed technical implementation details (optional)

Rather than passing as a parameter, since this is global and unique per resource (for debugging, we could have a mode where it doesn't clean up), it may be easiest to have dsc create a unique folder under the user temp location and pass it to the resource via the env var DSC_TEMP_PATH. So this env var is unique and provided at the start of the process. An adapter would either allow all its resources to use the same location or modify it per resource.