Use Eclipse Mars milestones as build target

Up to and including RAP 3.0.0 M4 the build used a Luna SR1 based target;
the results of this build were assembled twice, with components from
Luna SR1 and from Mars milestones.

The Luna dependencies are now removed and everything is using Mars
milestones now.

Change-Id: I8428fc8c78314c863989e3b8090d3030cf1882d0
Signed-off-by: Markus Knauer <mknauer@eclipsesource.com>