OSSM-6941: Update distro map for standalone ossm3 docs

Author: rh-tokeefe

_distro_map.yml

@@ -424,3 +424,13 @@ openshift-lightspeed:
     lightspeed-docs-1.0tp1:
       name: '1.0tp1'
       dir: lightspeed/1.0tp1
+openshift-service-mesh:
+  name: Red Hat OpenShift Service Mesh
+  author: OpenShift documentation team <openshift-docs@redhat.com>
+  site: commercial
+  site_name: Documentation
+  site_url: https://docs.openshift.com/
+  branches:
+    service-mesh-docs-3.0.0tp1:
+      name: '3.0tp1'
+      dir: service-mesh/3.0.0tp1