fix(gossip): improve gossip benchmarks

[0xNineteen]

these benchmarks are much better at measure per-message-type performance in a reliable way

we also update the readme to remove blog-post content and include more code-operator information

this PR also relies on #117 to be merged first (we needed the updated gossip stats struct)

---

results on a macbook pro

Benchmark                                  Iterations    Min(ms)    Max(ms)   Variance   Mean(ms)
-------------------------------------------------------------------------------------------------
benchmarkGossipService(10k_ping_msgs)               1       1489       1489          0       1489
benchmarkGossipService(10k_push_msgs)               1      11811      11811          0      11811
benchmarkGossipService(10k_pull_resp_msgs)          1      11761      11761          0      11761

Benchmark                                   Iterations    Min(ms)    Max(ms)   Variance   Mean(ms)
--------------------------------------------------------------------------------------------------
benchmarkPullRequests(1k_data_1k_pull_reqs)           1        528        528          0        528
benchmarkPullRequests(10k_data_1k_pull_reqs)          1        575        575          0        575