Enable optional recipe ggrc::local to run by default if available,

e.g. to install additional tools into the local deployment environment.
The (optional) recipe file is: `/site-cookbooks/ggrc/recipes/local.rb`

site-cookbooks/ggrc/recipes/default.rb

@@ -36,3 +36,10 @@
 end
 
 include_recipe "ggrc::package_env"
+
+# Attempt to include custom local additions to the environment
+begin
+  include_recipe "ggrc::local"
+rescue Chef::Exceptions::RecipeNotFound
+  # Fail silently, since the file is optional
+end