Implement runtime-configurable Grafana endpoints and database names

[LogicalGuy77]

fixes: #6

The changes add runtime-configurable Grafana support:

The backend reads new env vars (GRAFANA_PREFIX, GRAFANA_CPU_MEMORY_DB, GRAFANA_HTTP_REQUESTS_DB) and exposes them via a new /api/config endpoint; the frontend adds a ConfigService (with APP_INITIALIZER) to load that config at startup and updates GrafanaService, ServerInfoComponent and MetricsComponent to use the runtime values with robust fallbacks and error handling.

Tested it by running models web app with:

docker run -d \
  --name models-web-app-local \
  -p 5001:5000 \
  -v ~/kubeflow-proxy-config:/root/.kube/config:ro \
  -e APP_PREFIX=/ \
  -e APP_DISABLE_AUTH=True \
  -e APP_SECURE_COOKIES=False \
  -e KUBECONFIG=/root/.kube/config \
  -e BACKEND_MODE=dev \
  -e GRAFANA_PREFIX="/custom-grafana" \
  -e GRAFANA_CPU_MEMORY_DB="db/custom-cpu-memory" \
  -e GRAFANA_HTTP_REQUESTS_DB="db/custom-http-requests" \
  models-web-app:local-dev

[Griffin-Sullivan]

If we want to support this in a Kubeflow deployment we'll need to add it to the manifests

[Griffin-Sullivan]

@juliusvonkohout do we need to update https://github.com/kubeflow/manifests/blob/master/applications/kserve/models-web-app/overlays/kubeflow/kustomization.yaml#L18 too?

[juliusvonkohout]

@juliusvonkohout do we need to update https://github.com/kubeflow/manifests/blob/master/applications/kserve/models-web-app/overlays/kubeflow/kustomization.yaml#L18 too?

yes, all the configuration should be exposed in kustomize with the default values.

[Griffin-Sullivan]

After we merge we need to update the website to include the environment variables. See table in https://www.kubeflow.org/docs/components/kserve/webapp/#install-standalone

[juliusvonkohout]

Please ping me when you need a merge

[Griffin-Sullivan]

@juliusvonkohout looks good to me