storage_proxy: change reporting of estimated histograms
storage_proxy: change reporting of estimated histograms

We are currently collapsing the histograms in 16 points, exponentially
increasing in value, starting from 1.

While reducing the number of points is a worthy goal, the current
configuration caps us at 4ms. Our latencies tend to be higher than this.

Starting from 1 is also a bit of an exhaggeration: rarely are our
latencies in that range. This patch changes reporting so that we
report 20 points starting from 32.

Signed-off-by: Glauber Costa <7ba9037b0dd006f9408bd45b94707becd5cd4e87@scylladb.com>

avikivity/scylla,scylladb/scylla,duarten/scylla,duarten/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla,duarten/scylla,scylladb/scylla,avikivity/scylla