allow non-loggedin users to access public bucket (#5570)

* conditionally render main action buttons

- Make bucket action will be available only for loggedIn users
- File upload button will be avaialble for loggedIn users
  and non-loggedIn users if the prefix is writable

* select the bucket and prefix from the url

When the url contains bucket and prefix, it will be selected
by default instead of the first bucket from the list.

* show BucketSearch only for LoggedIn users

* allow non-LoggedIn users to access public bucket

* removed unused Router imports

* fix test case failures in BucketList.test.js

* remove dupicate minioBrowserPrefix from url

since history is already initialized with minioBrowserPrefix,
no need to use it in push or replace

* remove unused match from App component

* remove unused minioBrowserPrefix imports

browser/app/js/App.js

@@ -34,13 +34,15 @@ const AuthorizedRoute = ({ component: Component, ...rest }) => (
   />
 )
 
-export const App = ({ match }) => (
-  <Switch>
-    <AuthorizedRoute exact path={match.url} component={Browser} />
-    <Route path={`${match.url}/login`} component={Login} />
-    <AuthorizedRoute path={`${match.url}/:bucket/*`} component={Browser} />
-    <AuthorizedRoute path={`${match.url}/:bucket`} component={Browser} />
-  </Switch>
-)
+export const App = () => {
+  return (
+    <Switch>
+      <AuthorizedRoute exact path={"/"} component={Browser} />
+      <Route path={"/login"} component={Login} />
+      <Route path={"/:bucket/*"} component={Browser} />
+      <Route path={"/:bucket"} component={Browser} />
+    </Switch>
+  )
+}
 
 export default App