added back the coap service
added back the coap service

Signed-off-by: Jovan Kostovski <021cc6d606b455f44ff56c897e98eb759d8a0499@gmail.com>

Signed-off-by: Jovan Kostovski <021cc6d606b455f44ff56c897e98eb759d8a0499@gmail.com>

drasko/mainflux,Mainflux/mainflux-lite,drasko/mainflux,drasko/mainflux