Replace all cases where sequential flow ids are used with the generated high-entropy flow ids

[luizbarcelos]

After #3, the new extended classification flow is using the high-entropy flow ids (mca/flow_ids module). The task at hand is to replace all usages of sequential flow ids during the MCA flow with the generated high-entropy flow ids. The "flow ids" generated by the Identifier class (e.g. Identifiers's create_new_discovery_flow_id method) are merely indices to the high-entropy flow ids, not the flow ids themselves.