[oar-properties] add the gpu and gpudevice OAR properties.

Needed as soon as the gpu and gpudevice properties are created in all the OAR database, so that

• the jenkins script does not fail, like https://intranet.grid5000.fr/jenkins/job/test_oarproperties/site_cluster=lille-chetemi/2389/console
• the OAR properties wiki page knows about gpu.

lib/refrepo/gen/wiki/generators/oar_properties.rb

@@ -43,6 +43,10 @@ class OarPropertiesGenerator < WikiGenerator
       "description" => "The ID of the CPU the resource is part of. The unique scope is the OAR server. ",
       "possible_values" => "1, 2, 3, ..."
     },
+    "gpu" => {
+      "description" => "The ID of the GPU the resource is part of. The unique scope is the OAR server. ",
+      "possible_values" => "1, 2, 3, ..."
+    },
     "host" => {
       "description" => "A user-friendly name for the network_address property",
       "possible_values" => "dahu-1.grenoble.grid5000.fr, ..."