Implementing Comeonin behaviours

To implement the Comeonin and Comeonin.PasswordHash behaviours, create a module that use-s Comeonin and defines the hash_pwd_salt/2 and verify_pass/2 functions.

To test the implementation, use the helper functions in the Comeonin.BehaviourTestHelper module.

For an example implementation, see the lib/legacy_pbkdf2.ex and test/legacy_pbkdf2_test.exs files in LegacyPbkdf2.