Unique identifier of this resource within its enclosing namespace. In some scenarios, this id
is not user assignable. For files, this may be an system generated key, or the full path to
the resource. ex. /path/to/file.txt
A means to uniquely address this resource within a provider. For example, if the namespace of
a node or image is region based, the id will likely include both the region and the
provider-supplied id encoded to avoid collisions.