Move all composer files inside the common directory

- 2022년 3월 개발팀 결정사항 적용
- 모듈 등 서드파티 자료 개발시 composer를 사용하면 상위 경로에 있는 코어의
  composer.json을 수정하고, 코어의 vendor 디렉토리를 건드리는 것이 기본값임
- 이를 방지하기 위해 코어의 composer.json과 vendor를 common 디렉토리 안으로
  이동하여, 모듈 경로에서 상위 폴더로 인식하지 않도록 함

common/vendor/rmccue/requests/library/Requests/Proxy.php

@@ -0,0 +1,35 @@
+<?php
+/**
+ * Proxy connection interface
+ *
+ * @package Requests
+ * @subpackage Proxy
+ * @since 1.6
+ */
+
+/**
+ * Proxy connection interface
+ *
+ * Implement this interface to handle proxy settings and authentication
+ *
+ * Parameters should be passed via the constructor where possible, as this
+ * makes it much easier for users to use your provider.
+ *
+ * @see Requests_Hooks
+ * @package Requests
+ * @subpackage Proxy
+ * @since 1.6
+ */
+interface Requests_Proxy {
+	/**
+	 * Register hooks as needed
+	 *
+	 * This method is called in {@see Requests::request} when the user has set
+	 * an instance as the 'auth' option. Use this callback to register all the
+	 * hooks you'll need.
+	 *
+	 * @see Requests_Hooks::register
+	 * @param Requests_Hooks $hooks Hook system
+	 */
+	public function register(Requests_Hooks $hooks);
+}