Add in code to migrator to ensure collections get the proper permissions

[straleyb]

Descriptive summary

When the migrator runs it create collections bypassing some other hyrax code. The code that is bypassed adds in the permissions which allow discoverability for the collections as well as autocomplete on the relationships tab when creating a new work. This code needs to be added into the migrator to allow this process to take place during migration instead of after.

Expected behavior

When the migrator runs, it adds the Repository Administrators group to the collection which you can see when editing the collection.

Related work

Work done on #2877

Accessibility Concerns

N/A

[lsat12357]

Some clarification: the migrator code was not responsible for creating collections, this was done with a rake task, see https://github.com/OregonDigital/OD2/blob/master/lib/tasks/oregon_digital/create_collections.rake, and Brandon has updated that code.

[lsat12357]

QA Creating a single coll on staging. New instruction ran without incident once I remembered to save the coll; successfully added and removed the coll from a work.