Add managed certificate support and update ingress configuration for GKE

[ido777]

This pull request introduces small enhancement to the Open WebUI Helm chart, including the addition of managed certificate support and various ingress configuration options needed for https for improved deployment, while minimizing changes in the default values.yaml.

Key changes include:

Managed Certificate Support:

• Added a ManagedCertificate resource in managed-cert.yaml to enable automatic certificate management for specified domains.

Configuration Enhancements:

• Added values-gke-min.yaml to include working gke environment for "minimal" set up - only the main open-webui stateful set with no Ollama, Pipelines, Tika, Redis, and WebSocket support. This setup works with openai and it good as a starting point for deployment in GKE for a new comer. This meant to help users to overcome the issues I faced as new comer to add HTTPS.
• Added ingress with annotations for working with HTTPS, including SSL redirection and managed certificates, but left it disabled as it was in order not to change the default deployment at all.

These changes collectively improve the flexibility and ease of deploying Open WebUI on GKE with managed certificates and other configurable components.

[ido777]

@0xThresh I did the PR as you suggested, I also added a working examples for gke with minimal deployment that is a good starting point for new comer.

[0xThresh]

Hey @ido777, this looks much better and I'll be happy to merge this. One last change though, you still have some GKE values in values.yaml that are specific to GKE; can you please comment out the annotations in values.yaml? You're welcome to leave the updated host value.

Thanks for all your effort on the GKE values, I think that will be very helpful for folks!

[ido777]

fixed