Add support for converting custom NIC resource and its annotations to valid NGF specs

[salonichf5]

As a cluster operator
I want to be able to migrate from Ingress Resources in NIC to NGF
So that I am able support users to are migrating from NIC to NGF

Acceptance Criteria:

Plan and document how the VirtualServer, VirtualServerRoute and TransportServer that will be converted to NGF resources
Provide conversion support by reading both from file and cluster
Unit tests
Added documentation (Readme) on resources currently supported
PR in ingress2gateway repo