Add websocket benchmark + memory used + cpu % on number of connections per second etc

[ouvaa]

1. Add websocket benchmark on number of connections per second etc.
2. add memory used
3. add cpu % used
   for all benchmarks

[joanhey]

For now I think that websocket is not the direction of this benchmark.

And for the memory and cpu used, you can check this url:
https://ajdust.github.io/tfbvis/

Thank you.