* 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
This PR improves the documentation so that it is clear that this module does
not clean the repository metadata cache on removal, and add an example
notification handler to the removal example as an extra reminder.
This fixes#19730