* Remove nose from unittests
This PR migrates the last of our unittests from using nose to using
pytest. We don't need to install nose in our testing environments
anymore
* Update validate-modules
* Validates ANSIBLE_METADATA
* Ensures imports happen after documentation vars
* Some pep8 cleanup
* Clean up some left over unneeded code
* Update modules for new module guidelines and validate-modules checks
* Update imports for ec2_vpc_route_table and ec2_vpc_nat_gateway