PoC: Proper RESTful interface for big data import

To current PoC were added:
- new async server, that uses gevent.pywsgi (instead of gevent.wsgi)
- api-paste-async.ini and magnetodb-async-api-server.conf
- url parsing, getting tenant_name and table_name from it
(URL: /v1/{tenant_name}/data/tables/{table_name}/bulk_load)
- improve factory_method for bulk load application:
- getting cassandra endpoint from config
- getting oslo config arguments
- setup logging