Connection required on initialization

When instantiating a `GitHub::Ldap` object, a connection is established and query performed to determine the server's capabilities which are used to configure the appropriate membership search strategies.

I'd like to avoid having to connect and query on object instantiation and only perform the query when it's absolutely needed.

從 GitHub::Ldap 物件初始化開始，追蹤選擇成員搜尋策略的連線和伺服器能力查詢。確定哪些操作確實需要這些能力，然後驗證初始化會避免建立連線，同時所需的成員搜尋仍能取得正確的策略並查詢伺服器。

由索引模型根據 Issue 內容生成。