Add docker notary (#1036)

* updating the Build Action to sign docker images

* moving the DCT env var placement

* adding in some temp_test values to build/push the dev images

* testing dev docker signing

* debugging missing file

* adding manual creation of ~/.docker/trust/private since we are not building with DCT enabled

* updating the secret name for the delegation key passphrase

* removing debugging code

.github/test/on-master-event.json

@@ -0,0 +1,7 @@
+{
+  "release": {
+    "head": {
+      "ref": "master"
+    }
+  }
+}