Feature Request:: Unattended Install

==== Required information ====
- iRedMail version: 0.8.6
- Store mail accounts in which backend (LDAP):
- Linux/BSD distribution name and version: Centos 6.5
- Related log if you're reporting an issue:
====

Hi Zhang,

Is it possible to pre-answer the installation questions so that the whole thing sets up without user interaction?

thanks!