Make project_repositories_changelog Rate Limit Configurable Via Application Setting

In this MR: https://gitlab.com/gitlab-org/security/gitlab/-/merge_requests/4608 we added a rate limit to the projects :id/repository/changelog POST and GET endpoints.

The Gitlab Performance Tool is used to test endpoint performance under load, and disables application rate limits to do so. If a rate limit is not configurable, it can cause issues testing. Some additional context where a similar rate limit ran into some issues is here: https://gitlab.com/gitlab-org/quality/quality-engineering/team-tasks/-/issues/3253#note_2256131160

We should make the :id/repository/changelog rate limits configurable via an application setting.