Add different solutions to AWS exercises

Not only console solutions, but also Terraform and Pulumi.

In addition, this change fixes issues #279 and #280

topics/aws/exercises/new_vpc/terraform/main.tf

@@ -0,0 +1,11 @@
+resource "aws_vpc" "exercise-vpc" {
+  cidr_block       = "10.0.0.0/16"
+
+  tags = {
+    Name = "exercise-vpc"
+  }
+}
+
+output "vpc-id" {
+  value = aws_vpc.exercise-vpc.id
+}