tmf: Convert Delete trace dialog to a JFace dialog

tmf: Convert Delete trace dialog to a JFace dialog

It's the same functionality as before when it was a native dialog. But
now it allows us to control it in SWTBot.

Change-Id: I44af835a15bb00d2be6b294c837399caa23c83fb
Signed-off-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/75736
Reviewed-by: Hudson CI
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Tested-by: Matthew Khouzam <matthew.khouzam@ericsson.com>