[AXS-55] Rename DAC

[bernardoaraujor]

DAC is a legacy term. It was used by XAIN in the early days to reference the whole project.

We need a better name for this library. From now on, it must be called Access Secure Networking API, or ASN API.

It must be placed in the following structure:

└── network
    └── asn
        ├── asn_auth.c
        ├── asn_auth.h
        ├── asn_auth_helper.c
        ├── asn_auth_helper.h
        ├── asn_client.c
        ├── asn_debug.h
        ├── asn_internal.h
        ├── asn_server.c
        ├── asn_utils.c
        └── asn_utils.h

JIRA: AXS-55

[djordjeglbvc]

DAC is now moved and renamed to network/asn.

I have made slight change to directory structure, as there is an option for different encryption interfaces for ASN. Currently we have tinyembedded and SSL based (libCrypto) encryption implementations.

network/asn/
├── asn_auth.c
├── asn_auth.h
├── asn_auth_helper.c
├── asn_auth_helper.h
└── implementations
    ├── libCrypto
    │   ├── asn_client.c
    │   ├── asn_debug.h
    │   ├── asn_internal.h
    │   ├── asn_server.c
    │   ├── asn_utils.c
    │   └── asn_utils.h
    └── tinyembedded
        ├── asn_client.c
        ├── asn_debug.h
        ├── asn_internal.h
        ├── asn_server.c
        ├── asn_utils.c
        └── asn_utils.h

These implementations are chosen at build time, for now.

[djordjeglbvc]

Solved in #73