Ensure gitlab_kas.enabled, gitlab_kas.external_url and gitlab_kas.internal_url are set across all rails workloads

In gitlab-org/gitlab#299850 (closed) we added the rails configuration fields gitlab_kas.enabled, gitlab_kas.external_url and gitlab_kas.internal_url, as part of making the rails KAS-aware.

Before we can start relying on them on GitLab.com, we need to ensure they are set correctly.

For distribution specifics, see

• Omnibus MR: gitlab-org/omnibus-gitlab!5016 (merged)
• Chart MR: gitlab-org/charts/gitlab!1879 (merged)

Proposal

• Set external_url and enabled for k8s workloads (#1623 (comment 529867994) )
• Set external_url and enabled on chef-repo (#1623 (comment 529871427))
• Add load balancer specific options to the helm chart #1623 (comment 529867994)
• Blocked by the load balancer options: Set internal_url