lttng-guide: Update LTTng Kernel Analysis section

lttng-guide: Update LTTng Kernel Analysis section

Update existing sections (e.g. Control Flow view) and add new section
for CPU Usage analysis and view.

Change-Id: Iee748e2c9837a101760a9b5531a9c0800273378a
Signed-off-by: Bernd Hufmann <Bernd.Hufmann@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/27492
Reviewed-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>
Tested-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>
Tested-by: Hudson CI
Reviewed-on: https://git.eclipse.org/r/27565
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>