Fix netconf-tcp and netconf-ssh activators

Both of these activators have a dependency on netconf-util activating and exposing NetconfConfiguration, but this is not expressed in any way OSGi would understand and order the startup. This leads to sporadic failures to activate because netconf-util is scheduled to activate after netconf-ssh or netconf-tcp.

This is evidenced here:

https://logs.opendaylight.org/releng/vex-yul-odl-jenkins-1/autorelease-release-oxygen/184/console.log.gz

https://logs.opendaylight.org/releng/vex-yul-odl-jenkins-1/autorelease-release-oxygen/184/netconf/features/netconf/odl-netconf-ssh/target/surefire-reports/org.opendaylight.odlparent.featuretest.SingleFeatureTest-output.txt.gz

The simplest thing to do is to rewrite both netconf-ssh and netconf-tcp to use blueprint, so that the BP container starts only after netconf-util activates (i.e. NetconfConfiguration is published). Alternative is for the two activators to use a ServiceTracker – but that may prove too complex. In any case org.opendaylight.netconf.util.osgi.NetconfConfigUtil should be eliminated in the process.