Remove crypto polyfill

The FtM TS library relies on the Node.js `crypto` module (which isn’t available in browsers) in order to implement [namespace signatures](https://github.com/alephdata/followthemoney/blob/main/js/src/namespace.ts). The `crypto-browserify` polyfill is quite big and there were a few questions around continued maintenance of that project, so it would be good to remove it as an dependency.

I initially planned to update the namespacing implementation in the TS lib with the Web Crypto API which is available Node.js and browsers, but this would require breaking changes to the TS API as the Web Crypto API is async.

However, as far as I can see we do not actually rely on the TS implementation of namespaces in the UI, so we should be able to drop the polyfill without any further changes to the TS lib.

ui/craco.config.js

@@ -64,6 +64,18 @@ const svgIcon = (path, selectors) => {
 };
 
 module.exports = {
+  webpack: {
+    configure: (config) => {
+      return {
+        ...config,
+        resolve: {
+          fallback: {
+            'crypto': false,
+          },
+        },
+      };
+    },
+  },
   style: {
     sass: {
       implementation: sass,