Fix "Rubocop/Metrics/AbcSize" issue in app/controllers/moves_controller.rb

[ChaelCodes]

Assignment Branch Condition size for roll is too high. [15.39/15]

https://codeclimate.com/github/ChaelCodes/HuntersKeepers/app/controllers/moves_controller.rb#issue_600db476af985a00010000ef

[ChaelCodes]

Let's extract Roll into a separate service. This'll help us when we want to modify rolls with other moves.