feat: add Gateway API Route CR to loki-gateway

[mcharriere]

What this PR does / why we need it:

Add support for Gateway API Routes to loki's helm chart. The implementation is similar to grafana's own route.

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR

[CLAassistant]

All committers have signed the CLA.

[jkroepke]

Hey @mcharriere

The implementation is similar to grafana's own route.

I'm not fully convinced that the current simplicity and structure are sufficient in this case. While the Gateway object looks straightforward, the Ingress object at the root of the templates is quite complex.

If we want to introduce Gateway API support in the Loki Helm chart, the PR should at least include a Gateway API manifest that covers both:

• Gateway deployments
• Non-Gateway deployments (traditional ingress)

This is crucial to ensure the values.yaml structure works for both use cases. It would be a bad design decision to merge this PR, only to find out later that the current values setup doesn’t support additional HTTPRoute resources properly.

[jkroepke]

Suggested change

	- name: {{ include "loki.gatewayFullname" $ }}
	port: {{ $.Values.service.port }}
	- name: {{ include "loki.gatewayFullname" $ }}
	port: {{ $.Values.service.port }}
	group: ''
	kind: Service
	weight: 1

ref:

• [grafana] Add additional default value for HTTRoute backend helm-charts#3775
• [grafana] Add default values for HTTProute backendRefs helm-charts#3756

[jkroepke]

@mcharriere Do we still need this PR? If yes, please check my comments.