refactor: Add example of project with resource (#346)

This just adds the most minimal terraform script to provision a resource (the [`null_resource`](https://registry.terraform.io/providers/hashicorp/null/latest/docs/resources/resource)) that doesn't require a cloud provider.

With this, we can test creating projects that have an associated resource:
<img width="464" alt="Screen Shot 2022-02-21 at 2 31 54 PM" src="https://user-images.githubusercontent.com/88213859/155033757-372cafbf-b35f-4988-8fbe-af276e22421c.png">

examples/project-with-resource/main.tf

@@ -0,0 +1,17 @@
+# For interesting types of variables, check out the terraform docs:
+# https://www.terraform.io/language/values/variables#declaring-an-input-variable
+variable "message" {
+  type = string
+}
+
+# We can use a "null_resource" to test resources without a cloud provider:
+# https://www.terraform.io/language/resources/provisioners/null_resource
+resource "null_resource" "minimal_resource" {
+
+  # Note that Terraform's `provisioner` concept is generally an anti-pattern -
+  # more info here: https://www.terraform.io/language/resources/provisioners/syntax
+  # But it's helpful here for testing a resource.
+  provisioner "local-exec" {
+    command = "echo ${var.message}"
+  }
+}