feat(blockscout-stack): add Gateway API (HTTPRoute) support

[njegosrailic]

This PR adds support for Gateway API (HTTPRoute) resources to the blockscout-stack Helm chart, allowing users to use Gateway API as an alternative to or alongside traditional Kubernetes Ingress resources.

Closes #106

Changes

• Added gateway configuration sections to values.yaml for blockscout, frontend, stats, and user-ops-indexer components
• Created HTTPRoute templates: blockscout-httproute.yaml, frontend-httproute.yaml, stats-httproute.yaml, user-ops-indexer-httproute.yaml
• Support for Gateway API v1beta1 (and v1 for Kubernetes 1.27+)
• Maps existing Ingress path configurations to HTTPRoute path matches
• Backward compatible - existing Ingress configurations continue to work unchanged
• Ingress and Gateway API can be enabled simultaneously

Usage Example

blockscout:
  gateway:
    enabled: true
    gatewayRef:
      name: my-gateway
      namespace: default
    hostnames:
      - blockscout.example.com

Documentation

• Updated CHANGELOG.md with version 4.4.0 entry

Testing

I have tested this by exposing both the frontend and backend, and everything works as expected. Example:

apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  annotations:
    meta.helm.sh/release-name: blockscout
    meta.helm.sh/release-namespace: chain-alpha
  creationTimestamp: "2025-12-24T09:22:52Z"
  generation: 1
  labels:
    app.kubernetes.io/instance: blockscout
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: blockscout-stack
    app.kubernetes.io/version: 9.3.0
    helm.sh/chart: blockscout-stack-4.4.0
  name: blockscout-blockscout-httproute
  namespace: chain-alpha
  resourceVersion: "309600872"
  uid: 79fe4e41-77ca-48d4-8b61-d0bf261c296c
spec:
  hostnames:
  - blockscout.example.com
  parentRefs:
  - group: gateway.networking.k8s.io
    kind: Gateway
    name: internal
    namespace: default
  rules:
  - backendRefs:
    - group: ""
      kind: Service
      name: blockscout-blockscout-svc
      port: 80
      weight: 1
    matches:
    - path:
        type: PathPrefix
        value: /
status:
  parents:
  - conditions:
    - lastTransitionTime: "2025-12-24T09:22:52Z"
      message: Route is accepted
      observedGeneration: 1
      reason: Accepted
      status: "True"
      type: Accepted
    - lastTransitionTime: "2025-12-24T09:22:52Z"
      message: Resolved all the Object references for the Route
      observedGeneration: 1
      reason: ResolvedRefs
      status: "True"
      type: ResolvedRefs
    controllerName: gateway.envoyproxy.io/gatewayclass-controller
    parentRef:
      group: gateway.networking.k8s.io
      kind: Gateway
      name: internal
      namespace: default