feat: Add comprehensive documentation suite and reorganize project structure

- Created complete documentation in docs/ directory
- Added PROJECT_OVERVIEW.md with feature highlights and getting started guide
- Added ARCHITECTURE.md with system design and technical details
- Added SECURITY.md with comprehensive security implementation guide
- Added DEVELOPMENT.md with development workflows and best practices
- Added DEPLOYMENT.md with production deployment instructions
- Added API.md with complete REST API documentation
- Added CONTRIBUTING.md with contribution guidelines
- Added CHANGELOG.md with version history and migration notes
- Reorganized all documentation files into docs/ directory for better organization
- Updated README.md with proper documentation links and quick navigation
- Enhanced project structure with professional documentation standards

Google/Cache/Null.php

@@ -0,0 +1,57 @@
+<?php
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+if (!class_exists('Google_Client')) {
+  require_once dirname(__FILE__) . '/../autoload.php';
+}
+
+/**
+ * A blank storage class, for cases where caching is not
+ * required.
+ */
+class Google_Cache_Null extends Google_Cache_Abstract
+{
+  public function __construct(Google_Client $client)
+  {
+
+  }
+
+   /**
+   * @inheritDoc
+   */
+  public function get($key, $expiration = false)
+  {
+    return false;
+  }
+
+  /**
+   * @inheritDoc
+   */
+  public function set($key, $value)
+  {
+    // Nop.
+  }
+
+  /**
+   * @inheritDoc
+   * @param String $key
+   */
+  public function delete($key)
+  {
+    // Nop.
+  }
+}