storage_proxy: Add TRUNCATE verb handler
storage_proxy: Add TRUNCATE verb handler

scylladb/scylla,scylladb/scylla,duarten/scylla,kangkot/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla,kjniemi/scylla,avikivity/scylla,avikivity/scylla,kangkot/scylla,raphaelsc/scylla,duarten/scylla,duarten/scylla,kjniemi/scylla,raphaelsc/scylla,kjniemi/scylla,kangkot/scylla,raphaelsc/scylla