add number of cache reads received in custom payload to the trace#13

smaczliwka wants to merge 2 commits intozpp-2021-telemetry:scylla-3.xzpp-2021-telemetry/java-driver:scylla-3.xfrom

wprzytula:opentelemetry-parse-cache-counterwprzytula/java-driver:opentelemetry-parse-cache-counterCopy head branch name to clipboard