ctf.fs: split streams, one per port

ctf.fs: split streams, one per port

The ports are named `traceN-stream-STREAM`, where `N` is the index of
the trace (starts at 0) and `STREAM` is the base name of the stream
file.

The heap which used to be in this component class is expected to be
moved to the utils.muxer filter component class.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>