Transition to python 3.x primary gates

This patch renames the python 3.x jobs to be the main gate jobs and
renames the python 2.7 gates to -py2- gates.

Job aliases are included for the transition period in other repositories.

This is in preparation for python2.7 EOL[1].

[1] https://legacy.python.org/dev/peps/pep-0373/

Change-Id: I79e20152826b946dbdf7baa5d8999aeee1558f43
diff --git a/zuul.d/projects.yaml b/zuul.d/projects.yaml
index fc3b111..ad0a080 100644
--- a/zuul.d/projects.yaml
+++ b/zuul.d/projects.yaml
@@ -8,13 +8,13 @@
     check:
       jobs:
         - octavia-v2-dsvm-noop-api
-        - octavia-v2-dsvm-noop-api-stable-rocky
-        - octavia-v2-dsvm-noop-api-stable-queens
-        - octavia-v2-dsvm-noop-py35-api
+        - octavia-v2-dsvm-noop-py2-api
+        - octavia-v2-dsvm-noop-py2-api-stable-rocky
+        - octavia-v2-dsvm-noop-py2-api-stable-queens
         - octavia-v2-dsvm-scenario
-        - octavia-v2-dsvm-scenario-stable-rocky
-        - octavia-v2-dsvm-scenario-stable-queens
-        - octavia-v2-dsvm-py35-scenario
+        - octavia-v2-dsvm-py2-scenario
+        - octavia-v2-dsvm-py2-scenario-stable-rocky
+        - octavia-v2-dsvm-py2-scenario-stable-queens
         - octavia-v2-dsvm-scenario-centos-7:
             voting: false
         - octavia-v2-dsvm-scenario-ubuntu-bionic:
@@ -23,10 +23,10 @@
       queue: octavia
       jobs:
         - octavia-v2-dsvm-noop-api
-        - octavia-v2-dsvm-noop-api-stable-rocky
-        - octavia-v2-dsvm-noop-api-stable-queens
-        - octavia-v2-dsvm-noop-py35-api
+        - octavia-v2-dsvm-noop-py2-api
+        - octavia-v2-dsvm-noop-py2-api-stable-rocky
+        - octavia-v2-dsvm-noop-py2-api-stable-queens
         - octavia-v2-dsvm-scenario
-        - octavia-v2-dsvm-scenario-stable-rocky
-        - octavia-v2-dsvm-scenario-stable-queens
-        - octavia-v2-dsvm-py35-scenario
+        - octavia-v2-dsvm-py2-scenario
+        - octavia-v2-dsvm-py2-scenario-stable-rocky
+        - octavia-v2-dsvm-py2-scenario-stable-queens