Updated: tfvars.example, outputs.tf, Readme, Metal VRF Gateway module…

[davidlukemt]

…. Added: NSX-t Redundant Fabric VC token creation and Fabric VC token outputs. Removed: NSX-t uplink Metal Gateways and BGP Dynamic Neighbor range.

This PR changes the following:

• Main added second redundant interconnection Service Token pair for NSX-T Metal VLAN T0 Uplinks since VCF scripted T0 deployment doesn't support BGP Multi-hop required to peer with Metal VRF via BGP Dynamic Neighbor range.
• Outputs added new Fabric VC Service Tokens as well as Metal VRF Uplink tokens.
• Readme updated network architecture diagram, adds more deployment guidance, and output names.
• tfvars.example updated consistent comment formatting and removed NSX-T Uplink VLAN Subnet and BGP Dynamic Neighbor range.
• Metal VRF Gateway module added input logic to determine if Metal Gateway creation is desired/necessary based on input variables.
• variables.tf updated vcf_vrf_networks map definition making Subnet for Metal Gateway optional.