Replace gitlab.topology_service in favour of gitlab.cell.topology_service_client

What does this merge request do and why?

As per #2348 (moved), I am replacing gitlab.topology_service in favour of gitlab.cell.topology_service_client

How to set up and validate locally

1. Modify your gdk.yml as follows:

   cells:
     enabled: true
     instance_count: 1
     instances:
     - config:
         gitlab:
           cell:
             topology_service_client:
               enabled: true
               address: "127.0.0.1:50051"
               ca_file: /tmp/cell-2-ca-cert.pem
               certificate_file: /tmp/cell-2-client-cert.pem
               private_key_file: /tmp/cell-2-client-key.pem
   gitlab:
     cell:
       topology_service_client:
         enabled: true
         address: "127.0.0.1:50051"
         ca_file: /tmp/cell-1-ca-cert.pem
         certificate_file: /tmp/cell-1-client-cert.pem
         private_key_file: /tmp/cell-1-client-key.pem
   gitlab_topology_service:
     enabled: true

2. Run gdk reconfigure

   You should see a similar diff to the following appear:

   gitlab/config/gitlab.yml
   --------------------------------------------------------------------------------
   @@ -813,8 +813,8 @@ production: &base
          skip_sequence_alteration: true
        topology_service_client:
   -      address: 127.0.0.1:9095
   -      ca_file: /gdk/gitlab-topology-service/tmp/certs/ca-cert.pem
   -      private_key_file: /gdk/gitlab-topology-service/tmp/certs/client-key.pem
   -      certificate_file: /gdk/gitlab-topology-service/tmp/certs/client-cert.pem
   +      address: 127.0.0.1:50051
   +      ca_file: /tmp/cell-1-ca-cert.pem
   +      private_key_file: /tmp/cell-1-client-key.pem
   +      certificate_file: /tmp/cell-1-client-cert.pem

3. Check out this branch in the cells' directory:

   cd gitlab-cells/cell-2;
   git checkout tskorupa/refactor-gitlab-cells-configuration;
   cd ../..

4. Run gdk cells up

   You should see a similar diff to the following appear:

   gitlab/config/gitlab.yml
   --------------------------------------------------------------------------------
   @@ -807,4 +807,14 @@ production: &base
        # secret_file: /home/git/gitlab/.gitlab_workhorse_secret
   
   +  cell:
   +    enabled: true
   +    id: 2
   +    database:
   +      skip_sequence_alteration: false
   +    topology_service_client:
   +      address: 127.0.0.1:50051
   +      ca_file: /tmp/cell-2-ca-cert.pem
   +      private_key_file: /tmp/cell-2-client-key.pem
   +      certificate_file: /tmp/cell-2-client-cert.pem
   
      gitlab_kas:
   
   gitlab/config/session_store.yml
   --------------------------------------------------------------------------------
   @@ -1,4 +1,4 @@
    development:
   -  unique_cookie_key_postfix: true
   +  unique_cookie_key_postfix: false
      cookie_key: "_gitlab_session"
      session_cookie_token_prefix: "cell-2"
   ✅️ Cell 2 is ready.

5. Remove any replacements from gdk.yml:

   cells:
     enabled: true
     instance_count: 1
     instances:
     - {}
   gitlab_topology_service:
     enabled: true

6. Run gdk reconfigure

   You should see a similar diff to the following appear:

   gitlab/config/gitlab.yml
   --------------------------------------------------------------------------------
   @@ -813,8 +813,8 @@ production: &base
          skip_sequence_alteration: true
        topology_service_client:
   -      address: 127.0.0.1:50051
   -      ca_file: /tmp/cell-2-ca-cert.pem
   -      private_key_file: /tmp/cell-2-client-key.pem
   -      certificate_file: /tmp/cell-2-client-cert.pem
   +      address: 127.0.0.1:9095
   +      ca_file: /gdk/gitlab-topology-service/tmp/certs/ca-cert.pem
   +      private_key_file: /gdk/gitlab-topology-service/tmp/certs/client-key.pem
   +      certificate_file: /gdk/gitlab-topology-service/tmp/certs/client-cert.pem

7. Run gdk cells up

   You should see a. similar diff to the following appear:

   gitlab/config/gitlab.yml
   --------------------------------------------------------------------------------
   @@ -813,8 +813,8 @@ production: &base
          skip_sequence_alteration: false
        topology_service_client:
   -      address: 127.0.0.1:50051
   -      ca_file: /tmp/cell-2-ca-cert.pem
   -      private_key_file: /tmp/cell-2-client-key.pem
   -      certificate_file: /tmp/cell-2-client-cert.pem
   +      address: 127.0.0.1:9095
   +      ca_file: /gdk/gitlab-topology-service/tmp/certs/ca-cert.pem
   +      private_key_file: /gdk/gitlab-topology-service/tmp/certs/client-key.pem
   +      certificate_file: /gdk/gitlab-topology-service/tmp/certs/client-cert.pem
   
      gitlab_kas:
   ✅️ Cell 2 is ready.

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 MR references an issue describing the change.
• 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.