UPDATE: split the webapp in a widget and the app itself

This splits the webapp in:

* IronCalc (the widget to be published on npmjs)
* The frontend for our "service"
* Adds "dummy code" for the backend using sqlite

webapp/app.ironcalc.com/frontend/src/App.css

@@ -0,0 +1,10 @@
+#root {
+  position: absolute;
+  inset: 0px;
+  margin: 0px;
+  border: none;
+}
+html,
+body {
+  overscroll-behavior: none;
+}