Add bnd-parent

Add bnd-parent

https://bnd.bndtools.org/ which is used by maven-bundle-plugin, has
produced an alternative, nicer Maven integration with bnd-maven-plugin:
https://github.com/bndtools/bnd/tree/master/maven/bnd-maven-plugin

Since the way the plugin operates is significantly different, introduce
an alternative parent pom.xml, so that downstreams can migrate as they
choose.

Also convert bundles-test-lib to use this new capability.

JIRA: ODLPARENT-258
Change-Id: Ifa21ef51d95e88c5208aba35b3d6218da1f6eb1d
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>