Add support for private gateway (#154)

This change adds support for TCPRoutes when using a private gateway
class. This is similar to annotating services today. It also moves the
gateway classes to the Helm chart as it makes things a lot simpler for
the end user as they no longer have to define them.

Signed-off-by: Philip Laine <philip.laine@gmail.com>

examples/gateway-api/kubernetes.yaml

@@ -0,0 +1,13 @@
+apiVersion: gateway.networking.k8s.io/v1alpha2
+kind: TCPRoute
+metadata:
+  name: kubernetes
+  namespace: default
+spec:
+  parentRefs:
+  - name: private
+    namespace: netbird
+  rules:
+  - backendRefs:
+    - name: kubernetes
+      port: 443