API level refactoring

Now we have 2 API - REST and DynamoDB.
But both of those 2 APIs are implemented in single WSGI application
Now it becomes to be a problem for future features implementation

This patch separates tese 2 API on paste configuration level

Change-Id: Icf4edc5647f3a0fa5b87b51b133939a77d35ff97
Merge "API level refactoring"
Monitoring health check request

Also fixes bug with default content type

Implements: bp monitoring-health-check
Closes-bug: #1376834
Change-Id: I345c09b2ec623f1594adc1fb0967e7693c1a85a9
Use oslo.notify for notifications

Change-Id: I5a88204202ae6bfd19bb12c4e068e88960683eee
Blueprint: oslo-notify
Code cleanup

Delete redundant modules from magnetodb.openstack.common

Blueptint: review-openstack-common
Change-Id: Ibc75f37cc73e3eb30dc40cf47696173510be7f87