ctf: Use "meta events" for lost events (bug 408373)

ctf: Use "meta events" for lost events (bug 408373)

Instead of sending one event object for every single event reported as
lost in a CTF trace, only send one CTFEvent indicating how many events
were lost, in which time range.

On the TMF (ctfadaptor) side, we add a new CtfTmfLostEvent class to
wrap those. This way, only one entry shows up in the Events table,
indicating how many events were lost at that point in the trace.

Change-Id: I0c70ec2d5fc77134b67426d053a4d2353e710ab8
Signed-off-by: Simon Delisle <simon.delisle@ericsson.com>
Signed-off-by: Jean-Christian Kouamé <kadjo.gwandy.jean-christian.kouame@ericsson.com>
Signed-off-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Reviewed-on: https://git.eclipse.org/r/15491
IP-Clean: Matthew Khouzam <matthew.khouzam@ericsson.com>
Tested-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>