Remove deprecated CI lint page

What does this MR do?

Remove deprecated CI lint page. All it does is to say that lint page was moved under project settings. You can check it out at https://gitlab.com/ci/lint.

It was deprecated 2 years ago by gitlab-foss!17729 (merged). I believe its time we remove it.

Does this MR meet the acceptance criteria?

Conformity

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