Renamed ProtectedBranches::ApiUpdateService to LegacyApiUpdateService
What
Renames ProtectedBranches::ApiCreateService to ProtectedBranches::LegacyApiCreateService and similar for Update
Why
The module names currently give the impression they are used by the ProtectedBranches API, but they are only used by the deprecated protect/unprotect endpoints on the branches API. In https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/3516 I'm adding a service for the new API.