feat/metrics example

[cboudereau]

Add an example to support metrics/timers in stored procedure / sql in sybase

• use sp_sendmsg to send udp pakets
• create a script sample to find the best trafeoffs and alternative to a common stopwatch
• integrate metrics in prometheus with statsd-exporter adapter

Stopwatch tradeoff

Measuring delay with 2 dates is not recommended but to measure high latencies (> 1s since the precision is up to 1/300 second according to sybase documentation) without true stopwatch/timestamp, it is ok.