feat(observability): add http-server metrics and create example dashboards

What does this MR do and why?

This MR enhances our monitoring capabilities by improving the HTTP server metrics and creating example Grafana dashboards which can be used the tests the metrics and to create the production one.

• New Grafana examples dashboards:
  • Added a knowledge-graph: System Overview dashboard for high-level service health.
  • Added a knowledge-graph: HTTP Server dashboard with detailed metrics on request rates, error rates, and latencies per endpoint.
• Enhanced Metrics: Replaced the gkg_http_requests_total metric with gkg_http_responses_total, which now includes method, path, and status labels for more granular monitoring.

Related Issues

Part of #237 (closed)

Testing

I created the following dashboards to test out the metrics and I think they should be enough to observe the HTTP requests/responses for the server.

	Dashboard
Overview
Http server

Performance Analysis

• This merge request does not introduce any performance regression. If a performance regression is expected, explain why.