add Actions automation for running Terraform

* does not store terraform state anywhere; just imports it on every run
  * would be nice if there was a bulk import feature! the internal API
    seems to support it. hashicorp/terraform#22219
* doesn't run apply yet - pushing this for a dry run first.

part of #4

Signed-off-by: Alex Suraci <suraci.alex@gmail.com>

.github/workflows/terraform.yml

@@ -0,0 +1,50 @@
+name: 'Terraform'
+
+on:
+  push:
+    branches: [master]
+
+jobs:
+  terraform:
+    name: 'Terraform'
+    runs-on: ubuntu-latest
+    environment: production
+
+    defaults:
+      run:
+        shell: bash
+
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+
+    - name: Setup Terraform
+      uses: hashicorp/setup-terraform@v1
+      with:
+        terraform_version: 0.14.7
+
+    - name: Setup Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: 1.16
+
+    - name: Terraform Init
+      run: terraform init
+
+    - name: Terraform Format
+      run: terraform fmt -check
+
+    - name: Setup Vars
+      run: |
+        cat > .auto.tfvars <<EOF
+        github_token = "${{ secrets.ORG_ADMIN_GITHUB_TOKEN}}"
+        EOF
+
+    - name: Terraform Import
+      run: go run cmd/import/*.go
+
+    - name: Terraform Plan
+      run: terraform plan -refresh=false
+
+    # - name: Terraform Apply
+    #   run: terraform apply -auto-approve -refresh=false