Refactor SelectsCollections into service class

[atz]

https://github.com/projecthydra/curation_concerns/blob/99b38015bca4bb621c476325978293b755b7f131/app/controllers/concerns/curation_concerns/selects_collections.rb#L33-L37

The requirement of blacklight configuration means this is unavailable to non-controller code, but the functionality should certainly be available throughout the codebase, including to async jobs, reports, anywhere a User object exists, etc.

Refactor to permit something like:

CollectionService.collections_for_user_with_edit(blacklight_config, user)