[Network] Message : static attribute USER_INFO
[Network] NetworkServiceImpl : method implemented :
Revert "[Network] NetworkServiceImpl : method implemented :"

This reverts commit b20ef30a6afc7077f1841b88daba852ef0aa92b5.
[Network] NetworkServiceImpl - Method implemented addPeer(), sendUnicast() and userInfoBroadCast()

Implemented  :
addPeer() : adding a peer to the local hashmap
sendUnicast() : send a message to a peer
userInfoBroadcast() : send a multicast message to all the peer connected