Provide a performance testing framework

Workloads can be added to fdbserver in apple/foundationdb, but there is no provided framework for using them and configuring what test should be run with which settings. As a follow on from having a document of what to performance test from #1560, it would be nice to provide one canonical automation framework to create and run a real cluster utilizing these workloads that everyone can use.

Start by reviewing the existing workloads in fdbserver and the performance-testing document requested in #1560. Define how a canonical framework would configure workloads, create a real cluster, and run selected tests; done means the shared automation can execute these scenarios consistently.

Written by the indexing model from the issue text.