feat(GatewayAPI): Add timeouts for httpRoute

[Momotoculteur]

Description

Add support for configuring per-rule HTTPRoute timeouts in the Gateway API HTTPRoute template

Each entry under gatewayApi.rules now accepts an optional timeouts block exposing the two Gateway API fields:

• timeouts.request — maximum duration for the gateway to respond to a client request
• timeouts.backendRequest — timeout for an individual request from the gateway to the backend

Both values are Gateway API Duration strings (e.g. "30s", "500ms")

The field is rendered only when set, so existing installations are unaffected and the default rule behaviour is unchanged

Changes:

• templates/httproute.yaml: render timeouts for each rule when defined
• values.yaml: document the new timeouts field in the gatewayApi.rules example
• ci/gateway-api-timeouts.yaml: new CI values file covering a rule with custom request/backendRequest timeouts

Checklist:

• I have bumped the version in the Chart.yaml according to Semantic Versioning.
• I have updated the documentation/CHANGELOG at the bottom of the Chart.yaml
• I have signed off all my commits.
• (Optional) I have updated the Chart.lock for dependency updates
• (Optional) I have implemented helm tests for new feature flags