Add obsolete requests

and dropping some of the partials because it is duplicate code.

src/api/app/views/staging/staging_projects/_requests.xml.builder

@@ -0,0 +1,3 @@
+requests.each do |request|
+  builder.entry(id: request.number, creator: request.creator, state: request.state, package: request.first_target_package)
+end

src/api/app/views/staging/staging_projects/_staging_project_item.xml.builder

@@ -1,7 +1,16 @@
 builder.staging_project(name: staging_project.name, state: staging_project.overall_state) do
-  render(partial: 'staged_requests', locals: { staged_requests: staging_project.staged_requests, count: staging_project.staged_requests.count, builder: builder })
-  render(partial: 'untracked_requests', locals: { untracked_requests: staging_project.untracked_requests, count: staging_project.untracked_requests.count, builder: builder  })
-  render(partial: 'requests_to_review', locals: { requests_to_review: staging_project.requests_to_review, count: staging_project.requests_to_review.count, builder: builder  })
+  builder.staged_requests(count: staging_project.staged_requests.count) do
+    render(partial: 'requests', locals: { requests: staging_project.staged_requests, builder: builder })
+  end
+  builder.untracked_requests(count: staging_project.untracked_requests.count) do
+    render(partial: 'requests', locals: { requests: staging_project.untracked_requests, builder: builder })
+  end
+  builder.requests_to_review(count: staging_project.requests_to_review.count) do
+    render(partial: 'requests', locals: { requests: staging_project.requests_to_review, builder: builder })
+  end
+  builder.obsolete_requests(count: staging_project.staged_requests.obsolete.count) do
+    render(partial: 'requests', locals: { requests: staging_project.staged_requests.obsolete, builder: builder })
+  end
   render(partial: 'missing_reviews', locals: { missing_reviews: staging_project.missing_reviews, count: staging_project.missing_reviews.count, builder: builder })
   render(partial: 'building_repositories', locals: { building_repositories: staging_project.building_repositories, count: staging_project.building_repositories.count, builder: builder })
   render(partial: 'broken_packages', locals: { broken_packages: staging_project.broken_packages, count: staging_project.broken_packages.count, builder: builder })