Vite + TypeScript (#836)

Resolves #803

This is an initial commit to allow migrating to typescript bit by bit.
It introduces vite.
It removes all the webpack configuration (which I have no clue what all
the profiling are needed for, and couldn't find anything in the readme).
It also changes a single file from javascript to typescript:
`urlopen.js` -> `urlopen.ts`
Which was done manually, later on I'll see if I can automate most of the
migration.
For now, everything seems to work as expected.
I also upgrades storybook to use vite and renames the stories to jsx (I
honestly don't know why this complexity is needed here, but I'll keep it
for now).

cc: @damianstasik

stories/ModalLoading.stories.jsx

@@ -0,0 +1,22 @@
+import React from 'react';
+import ModalLoading from '../src/components/ModalLoading';
+import {Wrapper} from './ui';
+
+
+export default {
+  title: 'ModalLoading',
+  component: ModalLoading,
+};
+
+export const Basic = () => (
+  <Wrapper>
+    <div style={{maxHeight: "200px"}}>
+      <ModalLoading
+        isOpen={true}
+        title="Loading"
+        message="Loading 'something.geojson'"
+      />
+    </div>
+  </Wrapper>
+);
+