contrib/gocql/gocql: add WithErrorCheck

[ufoot]

Some cassandra services report a super high level of errors, when it's only queries returning no data because the selectors do not match. As show in the example, if you just SELECT ... something that is not in the DB -> returns as an error.

This only happens when using Scan though, using an iterator, the "problem" does not surface.

The patch uses ideas from #1314 and #1315 or #940 (already merged) and introduces a WithErrorCheck option with allows callers to consider that some errors should not be reported by APM.

A typical override would look like:

tq := WrapQuery(q,
		WithServiceName("TestServiceName"),
		WithErrorCheck(func(err error) bool { return err != gocql.ErrNotFound }))

[gbbr]

This is all good, but we need to apply the change differently.

[gbbr]

Thanks Christian 🙏🏻