change sim_mqtt_publish

[mohamedboubaker]

sim_mqtt_publish should include
The Client ID as an input with fixed length = 4 Bytes
The topic name with an maximum length of 64 Bytes
The message length which is variable with a maximum of 256

uint8_t sim_mqtt_publish(char * server_address, char * port, char * client_id, char * topic, uint8_t topic_length, char * message, uint8_t msg_length);