Add Requirements navigation link & page

Adds Requirements nav link to Projects nav sidebar and
placeholder page to host Requirements app.

app/views/layouts/nav/sidebar/_project.html.haml

@@ -159,6 +159,8 @@
                 %span.badge.badge-pill.count.merge_counter.js-merge-counter.fly-out-badge
                   = number_with_delimiter(@project.open_merge_requests_count)
 
+      = render_if_exists "layouts/nav/requirements_link", project: @project
+
       - if project_nav_tab? :pipelines
         = nav_link(controller: [:pipelines, :builds, :jobs, :pipeline_schedules, :artifacts], unless: -> { current_path?('projects/pipelines#charts') }) do
           = link_to project_pipelines_path(@project), class: 'shortcuts-pipelines qa-link-pipelines rspec-link-pipelines', data: { qa_selector: 'ci_cd_link' } do

ee/app/views/layouts/nav/_requirements_link.html.haml

+- return unless Feature.enabled?(:requirements_management, project)
+
+= nav_link(path: 'requirements#index') do
+  = link_to project_requirements_path(project), class: 'qa-project-requirements-link' do
+    .nav-icon-container
+      = sprite_icon('list-task')
+    %span.nav-item-name
+      = _('Requirements')
+  %ul.sidebar-sub-level-items
+    = nav_link(path: 'requirements#index', html_options: { class: "fly-out-top-item" } ) do
+      = link_to project_requirements_path(project) do
+        %strong.fly-out-top-item-name= _('Requirements')
+        %span.badge.badge-pill.count.requirements_counter.fly-out-badge
+    %li.divider.fly-out-top-item
+    = nav_link(path: 'requirements#index', html_options: { class: 'home' }) do
+      = link_to project_requirements_path(project), title: 'List' do
+        %span= _('List')

ee/app/views/projects/requirements/index.html.haml

-= _('Not Implemented')
+- page_title _('Requirements')
+
+-# haml-lint:disable NoPlainNodes
+%h1 Hello World from Requirements!

ee/spec/routing/project_routing_spec.rb

@@ -7,6 +7,12 @@ describe 'EE-specific project routing' do
     allow(Project).to receive(:find_by_full_path).with('gitlab/gitlabhq', any_args).and_return(true)
   end
 
+  describe Projects::RequirementsController, 'routing', type: :routing do
+    it "to #index" do
+      expect(get("/gitlab/gitlabhq/-/requirements")).to route_to('projects/requirements#index', namespace_id: 'gitlab', project_id: 'gitlabhq')
+    end
+  end
+
   # project_vulnerability_feedback  GET    /:project_id/vulnerability_feedback(.:format)     projects/vulnerability_feedback#index
   #                                 POST   /:project_id/vulnerability_feedback(.:format)     projects/vulnerability_feedback#create
   # project_vulnerability_feedback  DELETE /:project_id/vulnerability_feedback/:id(.:format) projects/vulnerability_feedback#destroy

locale/gitlab.pot

@@ -16763,6 +16763,9 @@ msgstr ""
 msgid "Require users to prove ownership of custom domains"
 msgstr ""
 
+msgid "Requirements"
+msgstr ""
+
 msgid "Requires approval from %{names}."
 msgid_plural "Requires %{count} more approvals from %{names}."
 msgstr[0] ""

spec/features/projects/navbar_spec.rb

@@ -18,6 +18,13 @@ describe 'Project navbar' do
     }
   end
 
+  let(:requirements_nav_item) do
+    {
+      nav_item: _('Requirements'),
+      nav_sub_items: [_('List')]
+    }
+  end
+
   let(:structure) do
     [
       {
@@ -54,6 +61,7 @@ describe 'Project navbar' do
         nav_item: _('Merge Requests'),
         nav_sub_items: []
       },
+      (requirements_nav_item if Gitlab.ee?),
       {
         nav_item: _('CI / CD'),
         nav_sub_items: [
@@ -100,6 +108,7 @@ describe 'Project navbar' do
   end
 
   before do
+    stub_licensed_features(requirements: false)
     project.add_maintainer(user)
     sign_in(user)
   end
@@ -123,5 +132,15 @@ describe 'Project navbar' do
 
       it_behaves_like 'verified navigation bar'
     end
+
+    context 'when requirements is available' do
+      before do
+        stub_licensed_features(requirements: true)
+
+        visit project_path(project)
+      end
+
+      it_behaves_like 'verified navigation bar'
+    end
   end
 end