Remove scopes/types for labels

app/assets/stylesheets/pages/labels.scss

app/controllers/projects/labels_controller.rb

app/helpers/labels_helper.rb

app/views/groups/labels/edit.html.haml

app/views/groups/labels/index.html.haml

app/views/groups/labels/new.html.haml

app/views/projects/labels/edit.html.haml

app/views/projects/labels/index.html.haml

app/views/projects/labels/new.html.haml

app/views/shared/_label_row.html.haml

spec/controllers/projects/labels_controller_spec.rb

spec/features/projects/labels/update_prioritization_spec.rb