Add support in HAProxy / Chef / Config Management for releasing Workspaces HTTP Server on .com

MRs:

Staging

• https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/12503+
• https://gitlab.com/gitlab-com/gl-infra/chef-repo/-/merge_requests/6549+
• Add workspaces (gitlab-cookbooks/gitlab-haproxy!435)
• Enabling Workspaces on staging (gitlab-com/gl-infra/production-engineering#27886 - moved)

Production

• ...

Description

Add support in HAProxy / Chef / Config Management for releasing Workspaces HTTP Server on .com as per the conversation in gitlab-com/gl-infra/production-engineering#27468 (comment 2786845164)

Acceptance criteria

• Workspaces HTTP Server is live on gstg. You should be able to create a workspace on staging and access it from the configured URL.
• Workspaces HTTP Server is live on gprd. You should be able to create a workspace on staging and access it from the configured URL.

Implementation plan

For each environment(gstg, gprd), do the following

• Define a pool for the environment (ref)
• Add an override for the port (ref)
• Add a backend definition in HAProxy (ref)
  • Add to enabled backends (ref) (This should be done on an environment level in chef-repo until rolled out to gprd)
• Add a frontend definition in HAProxy (ref)
  • Add to enabled frontends (ref) (This should be done on an environment level in chef-repo until rolled out to gprd)
• Add the 8160 port to the existing load balancer here
• Adds DNS records through config-mgmt in Terraform:
  • *.staging.gitlab.dev
  • kas.staging.gitlab.com