Adds vdu_id to message bus models

LB Dockerfile now uses Python3
Removes obsolete parameters from models
Refactors and fixes kafka integration tests
Refactors deprecated log warnings
Adds DATABASE env var to set MON database url
Fixes indentation and dependency issues in AWS plugin
Use open from io package for Python 2 and 3 compatibility

Signed-off-by: Benjamin Diaz <bdiaz@whitestack.com>
Change-Id: I70af22d2fbc2cb1bfd5d9632d9daa80e9d7f6b62