Move terraform state file

This lets me use the bucket for other states too

terraform/backends.tf

@@ -1,7 +1,7 @@
 terraform {
   backend "s3" {
     bucket  = "0rng-terraform"
-    key     = "terraform.tfstate"
+    key     = "infrastructure/terraform.tfstate"
     encrypt = true
     region  = "eu-west-2"
   }