Add helper method/module support to template resource

Adds helper methods to a template via the following syntax:

```
template "name" do
  # singular method definition:
  helper(:method_name) { method_body }

  # inline module definition
  helpers do
    def method_name
      method_body
    end
  end

  # external module inclusion
  helpers(MyHelperModule)
end
```

In each of the above cases, variables defined by Chef (e.g., `@node`)
or the user (via `:variables => {}`) can be accessed as normal.

Could use the following improvements:
- Template partials are not supported
- Input validation on Resource::Template should be improved
- Needs Unit tests for Template provider/implementation classes

1 files changed, 1 insertions, 0 deletions

diff --git a/spec/data/cookbooks/openldap/templates/default/helper_test.erb b/spec/data/cookbooks/openldap/templates/default/helper_test.erb
new file mode 100644
index 0000000000..92e6fe0427
--- /dev/null
+++ b/spec/data/cookbooks/openldap/templates/default/helper_test.erb
@@ -0,0 +1 @@
+<%= helper_method %>