little code modernization

[Lightning-]

this:

• adds a dependency to puppetlabs/stdlib (to be able to use ensure_resource())
• does some code optimizations/modernizations:
  • adds some param descriptions for puppet strings
  • improves datatypes
  • aligns a little bit more to styleguide (enum quotation e.g.)
  • replaces the ruby-alike function call each by the corresponding puppet function call
  • removes the if defined(Class[]) construction (as it might not be reliable) and uses ensure_resource() instead (in that context)

[saz]

Thanks!