Remove shade, nodepool, zuul from infra docs list

These have moved out of the infrastructure program and are no
longer published in these locations.

Change-Id: I70b8986bbcb52be09f6a23d8374a3865a79d9188
Depends-On: https://review.openstack.org/582305

docs-site/infra-documents.yaml

@@ -9,17 +9,11 @@ documents:
     directory: grafyaml
   - name: Jenkins Job Builder
     directory: jenkins-job-builder
-  - name: Nodepool
-    directory: nodepool
   - name: OpenStackID
     directory: openstackid
-  - name: Shade
-    directory: shade
   - name: Storyboard
     directory: storyboard
   - name: Python StoryBoard Client
     directory: python-storyboardclient
   - name: OpenStack CI
     directory: openstackci
-  - name: Zuul
-    directory: zuul