feat: add language endpoint

api/endpoint/language.php

+<?php
+require_once '../../config/config.php';
+require_once '../../app/core/App.php';
+require_once '../../app/core/Database.php';
+require_once '../../app/models/LanguageModel.php';
+
+$language_model = new LanguageModel();
+header('Content-Type: application/json');
+
+if ($_SERVER['REQUEST_METHOD'] === 'GET') {
+    $languages = $language_model->getAllLanguage();
+    $data = [
+        'status' => 'success',
+        'message' => $languages,
+    ];
+} else {
+    $data = [
+        'message' => 'Unsupported request method',
+    ];
+}
+echo json_encode($data);
+?>