Port poe messaging to JS

poe_graphql/SignupWithVerificationCodeMutation.graphql

@@ -0,0 +1,13 @@
+mutation SignupWithVerificationCodeMutation(
+    $verificationCode: String!
+    $emailAddress: String
+    $phoneNumber: String
+) {
+    signupWithVerificationCode(
+        verificationCode: $verificationCode
+        emailAddress: $emailAddress
+        phoneNumber: $phoneNumber
+    ) {
+        status
+    }
+}