feat(terraform): add aws_subnet resource for swarm-public-subnet to create a public subnet for the swarm cluster
feat(terraform): add aws_internet_gateway resource to create an internet gateway for the swarm VPC
feat(terraform): add aws_route_table resource to create a route table for the swarm VPC
feat(terraform): add aws_route_table_association resource to associate the swarm-public-subnet with the public route table