get_all_executions_in_stage(stage) in time order

[atripathy86]

When running cmflib/commands/artifact/pull.py , we are fetching all executions of a stage for a pipeline. Is there a guarantee that the executions returned will be in time order. Perhaps we should introduce an option to return a time ordered list. For example:

get_all_executions_in_stage(stage, ordered=True)

This becomes important if there are multiple executions (which have produced a given artifact) and the latest one needs to be pulled/returned. At this point all are returned, but which is the one that will be written to the remote filesystem? If there are multiple file hashes corresponding to a named file, its a matter of chance, what is pulled last. (Without time-ordering)

From pull.py run()

executions = query.get_all_executions_in_stage(stage)
            # check if stage has executions
            if len(executions) > 0:
                 # converting it to dictionary
                dict_executions = executions.to_dict("dict")
                # append id's of executions inside identifiers
                for id in dict_executions["id"].values():
                    identifiers.append(id)