Manage auth in test cases as a different entity, not as query/header parameters

[AML14]

This is critical for the correct handling of auth information in the evolving and mutation of test cases for the search-based module.

For the moment, the mutations removeParameter and crossTestCases can alter the auth information of several test cases.

As a workaround, what can be done is to look for the test data generator of the parameter. If it doesn't exist, then it's an auth parameter.