bug-2242: separating ofp applications

- created feature per app
  (of-switch-config-pusher, lldp-speaker, tableMissEnforcer)
- added essential apps to odl-openflowplugin-flow-service
  (of-switch-config-pusher, lldp-speaker)

Change-Id: I25f6595b9e6af47cf12ae05c7d4c76b0469222fa
Signed-off-by: Michal Rehak <mirehak@cisco.com>