feat: Rewrite of the core: avoid globals where possible

Create services for: login, status, router, database, AnonymousStatistics
Drop gesior.backward_support
Drop compat/pages.php
Drop part of compat/classes.php
Move signature to routes

system/functions.php

@@ -9,6 +9,7 @@
  */
 defined('MYAAC') or die('Direct access not allowed!');
 
+use MyAAC\App\App;
 use MyAAC\Cache\Cache;
 use MyAAC\CsrfToken;
 use MyAAC\Items;
@@ -599,10 +600,8 @@ function template_form()
 	return $twig->render('forms.change_template.html.twig', ['options' => $options]);
 }
 
-function getStyle($i)
-{
-	global $config;
-	return is_int($i / 2) ? $config['darkborder'] : $config['lightborder'];
+function getStyle($i) {
+	return is_int($i / 2) ? config('darkborder') : config('lightborder');
 }
 
 $vowels = array('e', 'y', 'u', 'i', 'o', 'a');
@@ -1210,7 +1209,7 @@ function clearCache()
 {
 	News::clearCache();
 
-	$cache = Cache::getInstance();
+	$cache = app()->get('cache');
 	if($cache->enabled()) {
 		$keysToClear = [
 			'status', 'templates',
@@ -1260,7 +1259,7 @@ function clearCache()
 	// routes cache
 	clearRouteCache();
 
-	global $hooks;
+	$hooks = app()->get('hooks');
 	$hooks->trigger(HOOK_CACHE_CLEAR, ['cache' => Cache::getInstance()]);
 
 	return true;
@@ -1314,9 +1313,6 @@ function getCustomPage($name, &$success): string
 				$tmp = $page['body'];
 
 			global $config;
-			if(setting('core.backward_support')) {
-				global $SQL, $main_content, $subtopic;
-			}
 
 			ob_start();
 			eval($tmp);
@@ -1685,6 +1681,15 @@ function getAccountIdentityColumn(): string
 	return 'id';
 }
 
+function app() {
+	static $_app;
+	if (!isset($_app)) {
+		$_app = new App();
+	}
+
+	return $_app;
+}
+
 // validator functions
 require_once SYSTEM . 'compat/base.php';