Modifies AutoDevOps yml script to include KUBE_INGRESS_BASE_DOMAIN

Note: This needs https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/24580 to be merged first

What does this MR do?

Modifies AutoDevOp.gitlab-ci.yml script to use KUBE_INGRESS_BASE_DOMAIN variable. Sets KUBE_INGRESS_BASE_DOMAIN based on AUTO_DEVOPS_DOMAIN if the first one doesn't exist to keep compatibility.

What are the relevant issue numbers?

Related to #52363 (closed)

Does this MR meet the acceptance criteria?

• [-] Changelog entry added, if necessary
• [-] Documentation created/updated via this MR
• [-] Documentation reviewed by technical writer or follow-up review issue created
• [-] Tests added for this feature/bug
• [-] Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• [-] Conforms to the database guides
• [-] Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• [-] Security reports checked/validated by reviewer