Pull in com.typesafe:config from odlparent

Pull in com.typesafe:config from odlparent

Along with an equivalent patch to netconf (forthcoming), this will
ensure the versions of com.typesafe:config are the same in both
projects, avoiding issues loading Karaf features in some cases
(e.g. odl-restconf-all from the netconf distribution).

This involves migrating features-akka to features-parent, which
requires support for extended version specifiers in odlparent
(I5033fae1ea13a31b1f2e3b97806829fe086e5f92). commons.odlparent is used
as an artifact POM to avoid having to duplicate properties, without
embarking on a whole-sale property clean-up (yet).

Change-Id: Ie557c8cb1634552acdf4762a5fe13a902a0ce8c2
Signed-off-by: Stephen Kitt <skitt@redhat.com>