Deprecate support for networking-vpp

The networking-vpp[1] project has been unmaintained. The code has not
been updated for 1.5 year and its CI has been broken for a while.

[1] https://opendev.org/x/networking-vpp

Change-Id: I7d9511455174830c801277d760ccf95e43d6cd29

manifests/agents/ml2/vpp.pp

@@ -1,5 +1,6 @@
 # == Class: neutron::agents::ml2::vpp
 #
+# DEPRECATED !!
 # Configure networking-vpp Neutron agent for ML2 plugin.
 #
 # === Parameters
@@ -61,6 +62,8 @@ class neutron::agents::ml2::vpp (
   include neutron::deps
   include neutron::params
 
+  warning('Support for the networking-vpp plugin has been deprecated.')
+
   resources { 'neutron_agent_vpp':
     purge => $purge_config,
   }

manifests/plugins/ml2/vpp.pp

@@ -1,4 +1,6 @@
+# == Class: neutron::plugins::ml2::vpp
 #
+# DEPRECATED !!
 # Install the networking-vpp ML2 mechanism driver and generate config file
 # from parameters in the other classes.
 #
@@ -39,6 +41,8 @@ class neutron::plugins::ml2::vpp (
   include neutron::deps
   require neutron::plugins::ml2
 
+  warning('Support for the networking-vpp plugin has been deprecated.')
+
   neutron_plugin_ml2 {
     'ml2_vpp/etcd_host':    value => $etcd_host;
     'ml2_vpp/etcd_port':    value => $etcd_port;

releasenotes/notes/deprecate-networking-vpp-aafae2fdafa2d896.yaml

@@ -0,0 +1,5 @@
+---
+deprecations:
+  - |
+    Support for the ``networking-vpp`` plugin has been deprecated and will be
+    removed in a future release.