Use a random squirrel id and an incremental nonce

Signed-off-by: Yohann D'ANELLO <ynerant@crans.org>

squinnondation/messages.py

@@ -227,13 +227,17 @@ class DataTLV(TLV):
                 sender.nickname = nickname
 
     @staticmethod
-    def construct(message: str) -> "DataTLV":
+    def construct(message: str, squirrel: Any) -> "DataTLV":
         tlv = DataTLV()
         tlv.type = 4
-        tlv.sender_id = 42  # FIXME Use the good sender id
-        tlv.nonce = 42  # FIXME Use an incremental nonce
+        tlv.sender_id = squirrel.id if squirrel else 0
+        tlv.nonce = squirrel.incr_nonce if squirrel else 0
         tlv.data = message.encode("UTF-8")
         tlv.length = 12 + len(tlv.data)
+
+        if squirrel:
+            squirrel.incr_nonce += 1
+
         return tlv