(PDB-254) WIP - Change benchmark to mutate catalog resources and edges send a defined number of messages

Previously benchmark.clj when it would mutate a catalog would only add a single resource.  This change will add a new resource or mutate a random existing resource.  It will also add a new or change an existing edge.  One of these four mutations is picked at random.  This commit also adds a new parameter to benchmark.clj to allow the syncronous sending of a specified number of commands (per host) via the -N argument.

Marked this as a WIP because I don't think that the -N/--nummsgs argument applies to reports.  I'm looking for feedback on that (see discussion in benchmark.clj below).