WIP : extract NetworkService
WIP : move stuff between network manager and network service.
      at this point there is about 700 lines of duplicated code
WIP: Leave creation of default offerings to NetworkManager init
WIP: clean up imports

Signed-off-by: Chiradeep Vittal <chiradeep@apache.org>
Remove old applyRules implementation
Clean up some unused imports
Fix mocks
Forgot some element adapters + dont add JuniperSRX by default