Refactorization of Module API

[christianparpart]

In the goal of refactoring the module API for mmsd, we - of course - have to rewrite all modules.

• Module API redesigned for simplicity of module implementation.
• move common logic from tcp module into the core module (such as group filtering)
• TCP (haproxy) module ported
• UDP module ported
• DNS module ported
• files module ported

Ideally (and especially TCP) the modules should be made more testable.