cockroachdb: add benchmarks

This change adds a benchmark that spins up a local CRDB cluster and
runs the kv workload against it.

Change-Id: I69684e5de3dc93d4c5ddeed84294fc3ed376b991
Reviewed-on: https://go-review.googlesource.com/c/benchmarks/+/588135
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
7 files changed