Add class to handle welcome rsa key

Currently this functionality lives internally
on modules using gerrit, and will be good if that
can be isolated on a class of the module.

Change-Id: I318e09ddbaedb2459b47e340a1826123a0dba52b

manifests/welcome.pp

@@ -0,0 +1,24 @@
+# == Class: gerrit::welcome
+#
+class gerrit::welcome (
+    $ssh_welcome_rsa_key_contents,
+    $ssh_welcome_rsa_pubkey_contents,
+) {
+  file { '/home/gerrit2/review_site/etc/ssh_welcome_rsa_key':
+    owner   => 'gerrit2',
+    group   => 'gerrit2',
+    mode    => '0600',
+    content => $ssh_welcome_rsa_key_contents,
+    replace => true,
+    require => File['/home/gerrit2/review_site/etc']
+  }
+
+  file { '/home/gerrit2/review_site/etc/ssh_welcome_rsa_key.pub':
+    owner   => 'gerrit2',
+    group   => 'gerrit2',
+    mode    => '0644',
+    content => $ssh_welcome_rsa_pubkey_contents,
+    replace => true,
+    require => File['/home/gerrit2/review_site/etc']
+  }
+}