Add support for Topology Service

What does this merge request do and why?

This MR adds support for the Topology Service within the HTTP router.

This update adds the Topology Service, enabling communication with the HTTP Router within the GDK.

How to set up and validate locally

1. Checkout the bojan/include-topology-service-within-http-router branch
2. Verify that you're having both Topology Service and HTTP router enabled:

   gdk config set gitlab_topology_service.enabled true
   gdk config set gitlab_http_router.enabled true

3. Run gdk reconfigure followed by gdk restart
4. You should be able to see the changes inside the Profile for Gitlab Http Router
5. Verify that everything works as expected 🎉

note: for checking that the Topology Service works as expected, we should update the classify.go file inside the GDK's gitlab-topology-service repo to include some kind of logging, e.g. (fmt.Println("Got request to classify FirstCell") inside the classifyFirstCell() function. Then, by running gdk tail gitlab-topology-service in your terminal, the following message should appear "Got request to classify FirstCell" 🦄

Impacted categories

The following categories relate to this merge request:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Merge request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise an issue to follow-up.
• Documentation added/updated, if needed.
• Announcement added, if change is notable.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.