FEATURE #1359: add views and controller for user management

This commit contains only placeholder files, not really working code.

app/Http/Controllers/Admin/UserManagement.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace App\Http\Controllers\Admin;
+
+use Illuminate\Http\Request;
+
+use App\Http\Requests;
+use App\Http\Controllers\Controller;
+
+class UserManagement extends Controller
+{
+    //
+}