Making changes to LBaaSHandler and Activator to add logic for LB Neutron calls.

- Cleaning up LBaaSHandler class to only handle the NEUTRON_LOAD_BALANCER event
- Cleaning up LBaaSHandler to only be INeutronLoadBalancerAware
- Adding the service LoadBalancerProvider and adding dependency in Activator
- Adding logic to handle the neutron LB instance creation call. After the call,
  the information will be stored in a Map <UUID, LoadBalancerConfiguration>
  object. Still TODO: FlowMods through the LoadBalancerService.

Change-Id: Ic20d10ea680730de59bbe60a12c47fc6684a6bab
Signed-off-by: Srini Seetharaman <srini.seetharaman@gmail.com>
Merge "Making changes to LBaaSHandler and Activator to add logic for LB Neutron calls."