Add organizations `index` and `new` routes

app/controllers/organizations/application_controller.rb

app/controllers/organizations/organizations_controller.rb

app/policies/base_policy.rb

app/policies/global_policy.rb

app/views/layouts/organization.html.haml

app/views/organizations/organizations/index.html.haml

app/views/organizations/organizations/new.html.haml

config/routes/organizations.rb

lib/sidebars/your_work/menus/organizations_menu.rb

lib/sidebars/your_work/panel.rb

locale/gitlab.pot

spec/lib/sidebars/your_work/menus/organizations_menu_spec.rb

spec/policies/global_policy_spec.rb

spec/requests/organizations/organizations_controller_spec.rb

...ng/organizations/organizations_controller_routing_spec.rb

spec/support/shared_contexts/navbar_structure_context.rb

spec/views/layouts/organization.html.haml_spec.rb