perf(autoloading): Add authoritative autoloader for theming

apps/theming/composer/autoload.php

@@ -0,0 +1,25 @@
+<?php
+
+// autoload.php @generated by Composer
+
+if (PHP_VERSION_ID < 50600) {
+    if (!headers_sent()) {
+        header('HTTP/1.1 500 Internal Server Error');
+    }
+    $err = 'Composer 2.3.0 dropped support for autoloading on PHP <5.6 and you are running '.PHP_VERSION.', please upgrade PHP or use Composer 2.2 LTS via "composer self-update --2.2". Aborting.'.PHP_EOL;
+    if (!ini_get('display_errors')) {
+        if (PHP_SAPI === 'cli' || PHP_SAPI === 'phpdbg') {
+            fwrite(STDERR, $err);
+        } elseif (!headers_sent()) {
+            echo $err;
+        }
+    }
+    trigger_error(
+        $err,
+        E_USER_ERROR
+    );
+}
+
+require_once __DIR__ . '/composer/autoload_real.php';
+
+return ComposerAutoloaderInitTheming::getLoader();

apps/theming/composer/composer.json

@@ -0,0 +1,13 @@
+{
+    "config" : {
+        "vendor-dir": ".",
+        "optimize-autoloader": true,
+        "classmap-authoritative": true,
+        "autoloader-suffix": "Theming"
+    },
+    "autoload" : {
+        "psr-4": {
+            "OCA\\Theming\\": "../lib/"
+        }
+    }
+}