New Onboarding Landing Page

Adding in a new landing page for onboarding. VirtualService should be as follows:

    apiVersion: networking.istio.io/v1alpha3
    kind: VirtualService
    metadata:
    name: onboarding
    spec:
    hosts:
        - "onboarding.t-rex.dsop.io"
        - "onboarding.preprod.dsop.io"
        - "onboarding.il2.dsop.io"
        - "onboarding.af.mil"
    gateways:
        - public-gateway.istio-system.svc.cluster.local
    http:
        - match:
            - uri:
                prefix: /
        rewrite:
            uri: /p1-onboarding/
        route:
            - destination:
                host: nginx
                port:
                number: 80