Add basic authentication support (#728)

* Move configuration in its own class in order to reduce the verbosity of index.php
* Add authentication mechanism using HTTP auth
* Add a method to get the config parameters
* Remove the installation checks from the index page
* Log all failed authentication attempts

lib/RssBridge.php

@@ -14,6 +14,8 @@ require __DIR__ . '/Bridge.php';
 require __DIR__ . '/BridgeAbstract.php';
 require __DIR__ . '/FeedExpander.php';
 require __DIR__ . '/Cache.php';
+require __DIR__ . '/Authentication.php';
+require __DIR__ . '/Configuration.php';
 
 require __DIR__ . '/validation.php';
 require __DIR__ . '/html.php';