feature: added merge_hardening for option-merging

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
feature: add getparam from puppetlabs/stdlib 4.2.1

this function is required for attribute overriding, but due to dependencies, it is not possible for everyone to pull in stdlib 4.x. So as an alternative, it is defined here, since it is mostly standalone as well.

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>