detect/flow: optimize only_stream/no_stream options

detect/flow: optimize only_stream/no_stream options

Until now the implementation would scan the stream, fallback to the
packet payload in exception cases, then keep track of where the match
was and in the flow match logic reject the match if it was in the wrong
buffer.

This patch simplifies this logic, by refusing to inspect the packet
payload when `only_stream` is set.

To do this the `only_stream`/`no_stream` options are now translated
to the pseudo protocols `tcp-stream` and `tcp-pkt` at parsing, so that
the `flow` keyword doesn't have to evaluate these conditions anymore.