Upgrade module to use ARC client VPN

[tsaucier-sf]

We need to update the source for the client_vpn to leverage the ARC Client VPN: https://github.com/sourcefuse/terraform-aws-arc-vpn/tree/main

The ARC VPN supports the "happy path" model we are looking to achieve by adding build-in support for multiple authentication methods.

terraform-aws-arc-network/main.tf

Line 67 in 2c59b55

module "client_vpn" {