Fix CI_SERVER_URL usage as it changes on external instances

Migrated issue

Reported by: fjgarlin

Related to !366 (merged) !356 (merged)

Problem/Motivation

#3522611: Add script to check "curl" return code and fail the job with clear message started using CI_SERVER_URL to simplify some code, but if the templates are used in another instance, then the code that uses the variable will not work as expected.

Steps to reproduce

https://project.pages.drupalcode.org/gitlab_templates/info/setup/#using-the-templates-in-another-instance

Proposed resolution

Add a new hidden variable DRUPALORG_CI_SERVER_URL with value 'https://git.drupalcode.org' for use in the curl statements and curl script.

Remaining tasks

MR

Related issue: Issue #3522611