Inline JS Removal for Merge Requests

What does this MR do?

Will remove all inline scripts in the area of merge requests

Why was this MR needed?

To get rid of the inline scripts once and for all

Does this MR meet the acceptance criteria?

• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

gitlab-org/gitlab-ce#34903