Improving perftest modularity

To help extending perf library this change seperates perf test across
serveral reusable modules :
  * initialize - start up all clients and gateways
  * setup - create databases and setup replication
  * start workload - run any kind of workload against clients
  * stop workload - stop any running workload against clients
  * statcollector - plug in monitoring and dashboard integration

scalability is improved by running workloads local to providers
instead of one master source loading all clients

also moves away from tap to give more benchmarking feel