added on nodes for rtdb and firestore andmade nodes pass through msg objects with as little changes as possible

firestore/firestore-get.html

@@ -53,4 +53,9 @@
 
 <script type="text/x-red" data-help-name="firestore-get">
     <p>A node that wraps the firestore-get SDK</p>
+    Get data from a document path in the firestore database
+<p>
+input: {"payload": {"path": "foo/bar"}}
+<p>
+output: <the document at the path "foo/bar" in the firestore database>
 </script>