in emqtt_private.h:
-> add struct Publisher and add a list of publisher in client

in EMqtt.h:
-> add register state and the definition of puback callback

in emqtt_client.c:
-> add puback and regack message management
-> add function to know existance of a publisher and an other function
to get a publisher following topic_name
-> add function register and publish

in emqtt_sn_sub.c:
-> add timer and functions to test register, publish and puback callback
-> subscribe is comment for testing others functionnalities