Mistral vim monitor task connects to conductor via conductor's AMQP
topic, calls the update_vim RPC method.
The RPC method will update vim and event DB entries and then return
passed in status.
This patch refactors the common_services_db and nfvo_db in order
not to import too many classes in the conductor process.
One more thing is on devstack, where tacker-conductor service is
introduced.
DocImpact
Implements: blueprint refactor-vim-monitor
Change-Id: Ic2b3c381cca796edc00f3c77cc790cb4c4955db7
755a55ad5f