Rename component includes caching MR

What does this MR do and why?

This MR renames the component includes caching from ci_optimize_component_fetching to ci_cache_component_includes. It also moves the flag from gitlab_com_derisk to ops type, which matches the convention of ci_cache_project_includes.

Note: Component includes caching will be disabled between the time when this MR is deployed and I enable the flag. Caching is just a performance optimization, so this shouldn't be a problem.

Rollout issue: [FF] Rollout `ci_cache_component_includes` - cr... (#596974 - closed)