Revert "Remove 'strong_parameters' matcher"

This reverts commit 7e7fb14677fac1e151c93becc3636e7f6731cf51.
Fix strong_parameters matcher

Remove dependency on Mocha and Bourne for strong_parameters matcher to
work. Instead, manually handle stubbing and mocking to provide platform
independence.
Clean up specs based on PR feedback
Memoize stubbed parameters class creation
Add documentation for `permit` matcher.
Standardize `failure_message` method naming