Change Done column to Closed in issue boards

app/assets/javascripts/boards/boards_bundle.js

...ets/javascripts/boards/components/sidebar/remove_issue.js

app/assets/javascripts/boards/models/list.js

app/assets/javascripts/boards/stores/boards_store.js

app/models/board.rb

app/models/list.rb

app/services/boards/create_service.rb

app/services/boards/issues/list_service.rb

app/services/boards/issues/move_service.rb

app/views/projects/boards/components/_board.html.haml

app/views/projects/boards/components/_board_list.html.haml

changelogs/unreleased/rename_done_to_closed.yml

doc/api/boards.md

spec/factories/boards.rb

spec/factories/lists.rb

spec/features/boards/boards_spec.rb

spec/features/boards/new_issue_spec.rb

spec/fixtures/api/schemas/list.json

spec/javascripts/boards/boards_store_spec.js

spec/models/list_spec.rb