Implement socket interface

[sebastianene07]

Describe the solution you'd like
Applications should be able to create a socket, bind to it and exchange data on it.
Implement the following API that will be exposed at the application layer:

     int socket(int domain, int type, int protocol); /* open a new communication endpoint and specified the desired interface */
     int bind(int socket, const struct sockaddr *address, socklen_t address_len); /* assign an address to our communication endpoint */
     ssize_t recv(int socket, void *buffer, size_t length, int flags);
     ssize_t send(int socket, const void *buffer, size_t length, int flags);

The initial implementation of the API should support conectionless operations. To test the API, a server & client app should be implemented that echos data back & forth using the local domain.