tmf: Bug 497413: Abstract time graph view JUL logger incorrectly enabled

tmf: Bug 497413: Abstract time graph view JUL logger incorrectly enabled

The time graph view abstract classes are changed to use their own class
when getting the logger so that they are in their own namespace and
inherit the Trace Compass parent logger's log level.

Change-Id: If117f307d8c12e601f26f97c57e6a26ba77311a6
Signed-off-by: Patrick Tasse <patrick.tasse@gmail.com>
Reviewed-on: https://git.eclipse.org/r/77347
Reviewed-by: Hudson CI
Reviewed-by: Genevieve Bastien <gbastien+lttng@versatic.net>
Tested-by: Genevieve Bastien <gbastien+lttng@versatic.net>