[CX] unable to create datasets on remote links when remote link is down

When a remote link is not reachable, any CREATE DATASET on that link will fail, as we expect the remote link to be as available as a Local link.  This hinders analytics application development, by requiring the remote link to be up and resources created up-front.  Such validation already occurs when connecting the link, it is onerous to force it at CREATE DATASET time.

On the other hand, having this validation when possible might help users not inadvertently target the wrong bucket/scope/collection name.  Perhaps in the remote link case, we should either issue a warning that the specified linkage is not possible, or add a keyword (e.g. FORCE) to indicate that, despite being valid, or able to be validated, the user wants to create it anyway. 

If and when we elect to backup & restore datasets created on remote links, we will likely require this behavior, as we will not have correct credentials at restore time, to validate associated datasets.