added warning page for browsers without streams downloading big files (#1175)

* added warning page for browsers without streams downloading big files

* fixed illustration size in Edge

* updated nostreams style

app/ui/downloadCompleted.js

@@ -0,0 +1,24 @@
+const html = require('choo/html');
+const assets = require('../../common/assets');
+
+module.exports = function(state) {
+  return html`
+    <div
+      id="download-complete"
+      class="flex flex-col items-center justify-center h-full w-full bg-white p-2"
+    >
+      <h1 class="text-center font-bold my-4 text-2xl">
+        ${state.translate('downloadFinish')}
+      </h1>
+      <p class="pb-2 text-grey-darkest leading-normal">
+        ${state.translate('downloadFinishText')}
+      </p>
+      <img src="${assets.get('completed.svg')}" class="max-w-sm" />
+      <p class="mb-4">
+        <a href="/" class="btn rounded-lg flex items-center mt-4" role="button"
+          >${state.translate('sendYourFilesLink')}</a
+        >
+      </p>
+    </div>
+  `;
+};