feat(aio): add initial angular-cli scaffold (#14118)

- adds initial CLI-generated app
- adds material toolbar
- initial (very rough) scss setup, lifted from angular/material
- initial routing scaffold w/ homepage

angular.io/database.rules.json

@@ -0,0 +1,6 @@
+{
+  "rules": {
+    ".read": "auth != null",
+    ".write": "auth != null"
+  }
+}