Merge branch 'remove-polyfill' into 'master'

fix: remove polyfill.io

See merge request !13

ui/frontend/public/index.html

@@ -41,9 +41,6 @@
       To begin the development, run `npm start` or `yarn start`.
       To create a production bundle, use `npm run build` or `yarn build`.
     -->
-    <!-- Polyfill for IE11, etc. -->
-    <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=default,Array.prototype.find,fetch"></script>
-
     <!-- Warn users about old browsers -->
     <script>
       var $buoop = {required:{e:-4,f:-3,o:-3,s:-1,c:-3},insecure:true,unsupported:true,api:2018.05 };