Add initial stab at JS vocoder script

vocoder/static/vocoder.js

@@ -0,0 +1,15 @@
+// Vocoder front-end Javascript
+
+// Only run our JS when everything on the page is loaded.
+// This includes images (our map tiles), see https://stackoverflow.com/a/1033448
+window.addEventListener('load', main)
+
+function main(){
+  const mappa = new Mappa('Leaflet');
+  // TODO: once we get the leaflet map setup, we'll overlay following
+  // the example from https://mappa.js.org/docs/examples-leaflet.html
+}
+
+// TODO: p5.js / mappa.js specifics for later ...
+function setup(){}
+function draw(){}

vocoder/templates/index.html

@@ -10,5 +10,6 @@
     Coming Soon TM.
     <script src="/static/leaflet/leaflet-src.js" charset="utf-8"></script>
     <script src="/static/mappajs/mappa.min.js" charset="utf-8"></script>
+    <script src="/static/vocoder.js" charset="utf-8"></script>
   </body>
 </html>