* 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
* Disassociate subnets from route tables before deletion
If a route table still has subnets associated with it, it will fail
to delete:
```
"msg": "The routeTable 'rtb-abcd1234' has dependencies and cannot be deleted."
```
Avoid this by disassociating subnets before route table deletion
* Fix ec2_vpc_route_table flake8 complaints
