3822: Added 'ensure_unique_name' option to #create method for API server to
choose a unique name when there is a name collision in the database.
arv-run-pipeline-instance checks to see if there is an output file with the
same name and contents, and uses 'ensure_unique_name' when creating collection.
3822: Fixed use of string instead of symbol in hash, added missing list separator.
3822: Updated Gemfile
Merge branch '3822-ensure-unique-names' refs #3822

Conflicts:
	services/api/Gemfile
	services/api/Gemfile.lock