Add odl-apache-spifly feature

We are headed towards requiring Woodstox as our SAX provider, which in turn requires spi-fly in the runtime environment.

While Karaf provides this integration, it is part of a huge 'spec' feature repository, which has a prohibitive cost in terms of offline repository.

Add a odl-asm and odl-apache-spifly features to allow seamless installation of just spifly.