added example for notifications erver validation

examples/notification_server/Dockerfile

examples/notification_server/RNIS/.keepme

...otification_server/RNIS/dummy_mec012_server/.dockerignore

...s/notification_server/RNIS/dummy_mec012_server/.gitignore

...n_server/RNIS/dummy_mec012_server/.swagger-codegen-ignore

..._server/RNIS/dummy_mec012_server/.swagger-codegen/VERSION

.../notification_server/RNIS/dummy_mec012_server/.travis.yml

...s/notification_server/RNIS/dummy_mec012_server/Dockerfile

...es/notification_server/RNIS/dummy_mec012_server/README.md

.../notification_server/RNIS/dummy_mec012_server/git_push.sh

...fication_server/RNIS/dummy_mec012_server/requirements.txt

...les/notification_server/RNIS/dummy_mec012_server/setup.py

...fication_server/RNIS/dummy_mec012_server/sub_payload.json

...erver/RNIS/dummy_mec012_server/swagger_server/__init__.py

...erver/RNIS/dummy_mec012_server/swagger_server/__main__.py

...ummy_mec012_server/swagger_server/controllers/__init__.py

...my_mec012_server/swagger_server/controllers/async_task.py

...er/swagger_server/controllers/authorization_controller.py

...mec012_server/swagger_server/controllers/dummy_service.py

...ec012_server/swagger_server/controllers/rni_controller.py