1. Proposed title of this feature request
[RFE] Remove dependency of istio-system namespace when creating gateways

2. What is the nature and description of the request?
When creating routes for gateways things get complicated as users have to create the gateway and the platform administrator must create the route in istio-system.

As an alternative, administrators can enable IOR which leverages the creation of the routes which works okay for plain http routes but it still is tricky for secure routes. Routes created by IOR are Passthrough routes (as seen in the code) and the secret must be created in istio-system namespace.

This still keeps a dependency of the developers with the platform administrator which is undesirable.

IOR could:

• check if there's a secret in the same namespace than the gateway with the name set in credentialName and use it and then (if there's no such secret) fallback to take it from istio-system. This would allow users to create their own secured routes for edge/reencrypt with their own certificates
• check if there's no credentialName field in the gateway definition in order to create an Edge route and not an Passthrough route, so the default wildcard certificate is used.

3. Why does the customer need this?
Avoid dependency of platform administrators when dealing with gateways as it's done for regular routes.

4. List any affected packages or components.
IOR