Update lib-forward-testing

The tempest-full job can replace the legacy job
legacy-tempest-dsvm-neutron-src since tempest installs the checked out
libraries, including the library under test. We have already converted
the py3 variant, and can convert the py2 the same way.

The Zuul v3 native tempest-full job is not available on stable/ocata, so
use the legacy job on ocata and older.

Move the template to project-templates file and add description.

Change-Id: Iac9162c1321f7f825684e1c20cc13ff5821d37d3

zuul.d/project-templates.yaml

@@ -1397,6 +1397,26 @@
         - infra-puppet-apply-4-ubuntu-xenial
         - openstackci-beaker
 
+- project-template:
+    name: lib-forward-testing
+    description: |
+      Run tempest, installing the library from source to ensure that
+      changes in the library do not break any of the services running
+      in devstack.
+    check:
+      jobs:
+        # Tempest-full is only working on pike and newer.
+        - tempest-full:
+            branches: ^(?!stable/(newton|ocata)).*$
+        - legacy-tempest-dsvm-neutron-src:
+            branches: ^stable/(newton|ocata)$
+    gate:
+      jobs:
+        - tempest-full:
+            branches: ^(?!stable/(newton|ocata)).*$
+        - legacy-tempest-dsvm-neutron-src:
+            branches: ^stable/(newton|ocata)$
+
 - project-template:
     name: lib-forward-testing-python3
     description: |

zuul.d/zuul-legacy-project-templates.yaml

@@ -73,15 +73,6 @@
         - neutron-grenade:
             branches: ^(?!stable/(newton|ocata)).*$
 
-- project-template:
-    name: lib-forward-testing
-    check:
-      jobs:
-        - legacy-tempest-dsvm-neutron-src
-    gate:
-      jobs:
-        - legacy-tempest-dsvm-neutron-src
-
 - project-template:
     name: lib-forward-testing-plugin
     check: