timing: Add a threadId field for the flame graph

timing: Add a threadId field for the flame graph

This creates a class for a thread that extends the
AggregatedCalledFunction class and having a field for the thread id.

This adds a new field for the thread id in the FlamegraphDepthEntry.

Change-Id: I9bd08039c9adc553e412cf0db6a8a788f786459b
Signed-off-by: Sonia Farrah <sonia.farrah@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/79074
Reviewed-by: Hudson CI
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Reviewed-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>
Tested-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>