Make yaml viz works with extensions other than .gitlab-ci.yml

What does this MR do?

Uses the util we have in ruby to determine if a file is a gitlab-ci config file which allow us to include custom names that can be defined per project basis that determine how your config file is named.

The feature is still behind a disabled feature flag, so there is no need for a changelog.

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Closes #249316 (closed)