Create VcnControlPlaneConfig and VcnControlPlaneIkeConfig

VcnControlPlaneConfig contains control plane configuration for
a VCN gateway connection. VcnControlPlaneIkeConfig is a
subclass that contains IKE configuration.

The followup CL will store VcnControlPlaneConfig in
VcnGatewayConnectionConfig.

Bug: 163604823
Test: FrameworksVcnTests(new tests added)
Change-Id: If7a85ae44e77fc4477b56ffa50c6e99ee96132d0