Microsoft has a guide on Deploying VPN Connections by Using Windows Powershell and Group Policy. The guide and script are a bit too verbose to fit into the format of a StackExchange answer. (17 page Word document + ~1200 lines of PowerShell + 70 lines of XML)
Depending on how you actually want to deploy the VPN configuration, you may not need the Group Policy portion of the guide. It's simply used to push out the PowerShell script and supporting XML file as part of a logon script.
The PowerShell functionality is summarized in the Solution Overview section:
PowerShell embeds C# code that is run as a part of the script. This article describes a sample PowerShell script that has C# code and calls the RAS API entry points to create and configure VPN connections settings. The input to the PowerShell script is an Extensible Markup Language (XML) file containing the configuration for the VPN connection. As a network administrator, you must customize the XML file for the VPN services in your organization.