VPN Installer with ready configuration

The supported way to do so is with the Fortinet EMS server. 

Back in Forticlient 6.0 you could have custom installation package in free version as well, not any more. 

Possible option to explore is configuring FC, then exporting its configuration (XML file), then importing it on new install. Whether/how it will work - cannot say. Here is a reference for that, worth trial - https://docs.fortinet.com/document/forticlient/7.0.1/xml-reference-guide/858086/ssl-vpn