Add optional Gateway API HTTPRoute template

[TJM]

Summary

Adds an optional templates/httproute.yaml that renders a gateway.networking.k8s.io/v1 HTTPRoute when gateway.enabled: true. Backend always points at this chart's Service (matching how ingress.yaml references the Service).

Bumps chart version 0.1.2 → 0.2.0 because this introduces a new templated resource (minor bump, not patch).

Motivation

Many GKE / mesh / Kubernetes-1.30+ setups use Gateway API instead of Ingress. The chart already supports ingress but had no Gateway API equivalent, forcing users to apply a sibling HTTPRoute manifest separately. With this change, a single helm install can attach the openspeedtest Service to a pre-existing shared Gateway.

Example values:

gateway:
  enabled: true
  parentRefs:
    - name: shared-gateway
      namespace: gateway
      sectionName: https
  hostnames:
    - speedtest.example.com

Design notes

• Disabled by default — gateway.enabled: false, so existing installs render no change.
• No Gateway resource is created — only the HTTPRoute. Gateways are typically shared infrastructure provisioned outside the chart.
• Backend is the chart's own Service — same {{ include "openspeedtest.fullname" . }} pattern used by ingress.yaml, so multiple route types stay consistent.
• hostnames is optional. When empty, the route matches every hostname the parent Gateway accepts.
• matches is optional. When empty, the rule matches every path.
• parentRefs is required when enabled (no sensible default).

Changes

• templates/httproute.yaml — new template guarded by .Values.gateway.enabled.
• values.yaml — add gateway: section after ingress: with the same disabled-by-default + commented-example style.
• Chart.yaml — bump version 0.1.2 → 0.2.0.

Test plan

• helm lint passes.
• helm template with gateway.enabled: false (default): no HTTPRoute is emitted.
• helm template with gateway.enabled: true + parentRefs/hostnames/matches: HTTPRoute renders matching the spec.
• helm template with gateway.enabled: true + matches: []: HTTPRoute renders without a matches block (catch-all route).
• End-to-end verified on a real GKE cluster: chart-deployed HTTPRoute attaches to a Gateway (rilb-gateway) and routes traffic to the chart's Service.