Remove dirctl dependency

[csirmazbendeguz]

As far as I understand, the dirctl command is only used for the sign and verify operations

If possible, let's implement these operations in the SDK itself so there's no need to depend on dirctl anymore

[arpad-csepi]

The native implementation is tedious and verbose for sign and verify functions and does not scale well for later local operated functions. This issue will be re-evaluated later with an another PoC using Web Assembly or other C based library implementation for the non gRPC based functionalities.