Split RawSpan to Spans buffer and Events buffer

[tonyredondo]

We need to change the recorder to split the RawSpan and store the Span and the Events in two separated buffers. So in each payload we send up to a max number of spans and events.

Currently the tracer is configured to store up to 10000 events per spans, and the recorder has a RawSpan buffer, so we can end up with 1...2 or 3 spans with 10000...20000...30000 events....