Added CLI installer

This adds the ability to send a post request to `installer/index.php/quick_installer` with post variables or you can use environmental variables. Needed a CLI installer to provision pyrocms with [protobox](https://github.com/protobox/protobox). Here is an example bash file aswell:

```
#!/bin/bash
export TERM=dumb

export pyrocms_database="pyrocms"
export pyrocms_hostname="localhost"
export pyrocms_username="root"
export pyrocms_password="root"
export pyrocms_port="3306"
export pyrocms_http_server="apache_w"
export pyrocms_site_ref="default"
export pyrocms_user_name="admin"
export pyrocms_user_firstname="Admin"
export pyrocms_user_lastname="Admin"
export pyrocms_user_email="admin@admin.com"
export pyrocms_user_password="admin"

cd installer && php index.php quick_installer
```