Feature: OpenTelemetryExtension field/operation exclusion list

[dhay]

Our GraphQL application has a "health check" query field that we use to assess the health of the service. Needless to say, this query makes up the vast bulk of the traces in our system. It would be nice if there were a way to configure the OpenTelemetryExtension with an exclusion list of fields. Alternatively, perhaps provide a filter function, similar to what is done for filtering args. i.e. something like this in the resolve method:

if not should_trace(info) or not self._field_filter(obj, info):
    return next_(obj, info, **kwargs)