We want to have consistent rate limits across project/group import
and exports. Update all these endpoints to use matching rate keys and
scopes.

Also increase export rate limit to be consistent with the import rate
limit as currently the export limit is to restrictive.

MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/33026

Original issue: https://gitlab.com/gitlab-org/gitlab/-/issues/212707