Install host key

Create a new script to install karaf host.key on ODL installation.
Also, updated base ODL container to move ODL base distribution
directory to /opt/opendaylight/current and create a symlink with
the original name.  This is done to allow OOM to support an external
mount to /opt/opendaylight/current/daexim to preserve backups.

Change-Id: I048b7d8002636dcd4ffbdff7242eb40d2a2787da
Issue-ID: CCSDK-241
Signed-off-by: Timoney, Dan (dt5972) <dt5972@att.com>