Deprecate support for Cisco VTS mechanism driver

This implementation has not had any meaningful update for past 5 years.
The driver code is not publicly available so we can't know if our
current implementation is compatible with recent releases.

Change-Id: I395bbed2d7f311e7ce94d32b37746da878e44db9

manifests/plugins/ml2/cisco/vts.pp

@@ -1,5 +1,6 @@
-# == Define: neutron::plugins::ml2::cisco::vts
+# == Class: neutron::plugins::ml2::cisco::vts
 #
+# DEPRECATED !!
 # Install the Cisco VTS driver and generate the ML2 config file
 # from parameters in the other classes.
 #
@@ -56,6 +57,8 @@ class neutron::plugins::ml2::cisco::vts (
   include neutron::deps
   require neutron::plugins::ml2
 
+  warning('Support for Cisco VTS mechanism driver has been deprecated')
+
   ensure_resource('package', 'python-cisco-controller',
     {
       ensure => $package_ensure,

releasenotes/notes/deprecate-cisvo-vts-d8af24f540ecb86a.yaml

@@ -0,0 +1,4 @@
+---
+deprecations:
+  - |
+    Support for Cisco VTS mechanism driver has been deprecated.