MDMailbox 账户绑定 Account绑定多邮箱 定时拉取新邮件 新未读邮件提醒 数据存储 绑定关系 { aid: "AccountId", mail: "Email Address", type: "IMAP | POP3 | SMTP", token: "password", ssl: "boolean", server: "imap.qq.com | pop.qq.com | smtp.qq.com", port: "995", time: "" }