Set up SpamAssassin

Scan incoming and outgoing email for spam. Use a local Unbound for DNS,
so we don't run into blocks for RBL queries.

cookbooks/unbound/resources/package.rb

@@ -0,0 +1,36 @@
+#
+# Cookbook:: unbound
+# Resource:: package
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+unified_mode true
+
+provides :unbound_install
+
+property :packages, [String, Array],
+          coerce: proc { |p| p.is_a?(Array) ? p : [ p ] },
+          default: %w(unbound),
+          description: 'Unbound packages to install.'
+
+action_class do
+  def do_package_action(action)
+    package 'unbound' do
+      package_name new_resource.packages
+      action action
+    end
+  end
+end
+
+%i(install upgrade remove).each { |pkg_action| action(pkg_action) { do_package_action(action) } }