chore: adding a benchmark utility in client.

[arpan14]

• The existing setup using JMH produces flaky results at time due to thread safe scope variables and also it lacks the ability to pass different parameters from command-line.
• This is a more light-weight setup which allows to pass params from command-line and keeps the setup much simpler.
• This util also allows us to export metrics/traces directly to cloud monitoring so that its easy to visualize and compare stats.