This MR brings a new devtools benchmark that aims to quantify the number of Request Per Seconds (RPS) that a node can handle.

See detailed description of the benchmark in the README file introduced

Manually testing the MR

This can be run locally following the instruction steps proposed in the README. There is no automated tests.

Checklist

Document the interface of any function added or modified (see the coding guidelines)
Document any change to the user interface, including configuration parameters (see node configuration)
Provide automatic testing (see the testing guide).
For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
Select suitable reviewers using the Reviewers field below.
Select as Assignee the next person who should take action on that MR