statesystem : Add a default compareTo() for segments

statesystem : Add a default compareTo() for segments

Implements a default compareTo() in ISegment. The comparison will be
based on the start and the end of the segment. Subclasses could extend
this default behaviour if needed.
Also, the interface become Comparable<@NonNull ISegment>.

Change-Id: Ib58e0ba80c0151d127254c8b87eafec57e624566
Signed-off-by: Jean-Christian Kouame <jean-christian.kouame@ericsson.com>
Signed-off-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/67620
Reviewed-by: Genevieve Bastien <gbastien+lttng@versatic.net>
Tested-by: Genevieve Bastien <gbastien+lttng@versatic.net>