Expose CI include links

What does this MR do and why?

We want to show included files on the CI Linter page. To do that, backend needs to send this information to frontend via the ciConfig result.

In this MR, I removed the merged_yaml attribute from Ci::Pipeline and added config_metadata instead. This will store all on-the-fly config metadata.

Related to #344937 (closed)

This MR is based on !81982 (merged).

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