hello3: Add verbs

Add the following verb for testing purpose:

 - close:    close the session
 - set-loa:  set the LOA of the session
 - setctx:   set the contextual data of a session
 - setctxif: set the contextual data of a session if not already set
 - getctx:   get the contextual data of a session
 - info:     returns the info of the session

Change-Id: Ie2ceb897ecdff01f6efd0a3b174b5794913726d9
Signed-off-by: José Bollo <jose.bollo@iot.bzh>