Upgrade Web UI to Create-React-App 4 and React 17 (#1105)

* Upgrade to CRA 4.0.3

* Try to fix tests. No lucky

* Fix new ESLint errors

* Fix JS tests and remove unwanted dependency. (#1106)

* Fix tests

* Fix lint

* Remove React v16 workaround (fixed in v17)

* Force eslint to break on warnings

* Lint now needs to be called explicitly in the pipeline

Co-authored-by: Yash Jipkate <34203227+YashJipkate@users.noreply.github.com>

ui/src/routes.js

@@ -2,4 +2,6 @@ import React from 'react'
 import { Route } from 'react-router-dom'
 import Personal from './personal/Personal'
 
-export default [<Route exact path="/personal" render={() => <Personal />} />]
+const routes = [<Route exact path="/personal" render={() => <Personal />} />]
+
+export default routes