CCryptoControl: Partially removed dependency on CUDT.

[maxsharabayko]

CCryptoControl takes too much responsibility, and also handles sending of KM packets via a CUDT socket class.
Ideally, the CUDT should send everything itself, and only ask CCryptoControl if something has changed and an exchange of updated keys is required. However, it is not easy to decouple this logic straight away.
This PR removed reference to CUDT where possible. When CUDT asks CCryptoControl to send something, it just passes a pointer to itself so that CCryptoControl can call the sending function.
This should at least allow using CCryptoControl in a unit test without mocking CUDT.