Add placement to the shared service components

Placement is fully extracted now, under its own governance, and
deleted from nova, so it should probably show up on "the map".

Change-Id: I03f9d9b2ae452d6a3328fa9dc364191dcfee3142

openstack_components.yaml

@@ -266,6 +266,17 @@ tabs:
             project-team: keystone
             since: Essex
 
+          - name: Placement
+            title: Placement service
+            docs-title: Docs
+            docs-url: https://docs.openstack.org/placement/latest/
+            desc: >
+              Placement is an OpenStack service that provides an HTTP API for
+              tracking cloud resource inventories and usages to help other
+              services effectively manage and allocate their resources.
+            project-team: placement
+            since: Stein
+
           - name: glance
             title: Image service
             docs-title: Docs