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/index.js

@@ -21,10 +21,10 @@ import "material-design-iconic-font/dist/css/material-design-iconic-font.min.css
 
 import React from "react"
 import ReactDOM from "react-dom"
-import { BrowserRouter, Route } from "react-router-dom"
+import { Router, Route } from "react-router-dom"
 import { Provider } from "react-redux"
 
-import { minioBrowserPrefix } from "./js/constants"
+import history from "./js/history"
 import configureStore from "./js/store/configure-store"
 import hideLoader from "./js/loader"
 import App from "./js/App"
@@ -33,9 +33,9 @@ const store = configureStore()
 
 ReactDOM.render(
   <Provider store={store}>
-    <BrowserRouter>
-      <Route path={minioBrowserPrefix} component={App} />
-    </BrowserRouter>
+    <Router history={history}>
+      <App />
+    </Router>
   </Provider>,
   document.getElementById("root")
 )