[QAEngine] Url slug, Captcha, Mailing

1. Url slug:

This section allows you to insert all the slugs for your site. Choose Engine settings > Settings > URL slug 

2. Captcha:

Enable this option you can prevent spammers from registering and posting. 

3. Mailing:

You can create your own templates for Register Mail, Confirmation Mail, Confirmed Mail, Forgotpass Mail, Resetpass Mail, Pending Questions Mail, New Answer Mail, Report Mail, Best Answer Mail, Ban User Mail, Inbox Mail. For example, there is a template for register mail in the photo below.