Changes

ctf.core: Parse data stream of a trace

Implement parsing of data streams for CTF2 Traces. Testing of this patch
is postponed until after the follow-up patch [1].

[1]https://git.eclipse.org/r/c/tracecompass/org.eclipse.tracecompass/+/203295

Change-Id: I6ce9273e46b1e970a77354346fb5814b061d2c81
Signed-off-by: Sehr Moosabhoy <sehr.moosabhoy@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/c/tracecompass/org.eclipse.tracecompass/+/203294
Tested-by: Trace Compass Bot <tracecompass-bot@eclipse.org>
Tested-by: Marco Miller <marco.miller@ericsson.com>
Reviewed-by: Marco Miller <marco.miller@ericsson.com>