Add skeleton of yardoc face

Currently just reads in a path to a `.pp` file and runs it through a Pops
parser.

lib/puppet/application/yardoc.rb

@@ -0,0 +1,4 @@
+require 'puppet/application/face_base'
+
+class Puppet::Application::Yardoc < Puppet::Application::FaceBase
+end

lib/puppet/face/yardoc.rb

@@ -0,0 +1,16 @@
+require 'puppet/face'
+require 'puppet/pops'
+
+Puppet::Face.define(:yardoc, '0.0.1') do
+
+  action(:yardoc) do
+    default
+
+    when_invoked do |*args|
+      parser = Puppet::Pops::Parser::Parser.new()
+      parse_result = parser.parse_file(args[0])
+
+      return 0
+    end
+  end
+end