The `app/controllers/projects/boards_controller.rb` is identical to
the CE version by doing this.

I've split up the `spec/controllers/projects/boards_spec.rb` into the
logic that is on CE en what is on EE. However, they have diverged. So
they are likely (however less than before) to cause conflicts in the
future.

We'd need to move the EE specific spec logic for
`Projects::BoardsController#index` & `Projects::BoardsController#show`
into `spec/controllers/ee/projects/boards_controller.rb` however, some
of the tests in EE have been improved, so those improvements would
need to be ported to CE.