Migrate over to using pyosmocom

We're creating a 'pyosmocom' pypi module which contains a number of core
Osmocom libraries / interfaces that are not specific to SIM card stuff
contained here.

The main modules moved in this initial step are pySim.tlv, pySim.utils
and pySim.construct. utils is split, not all of the contents is
unrelated to SIM Cards.  The other two are moved completely.

Change-Id: I4b63e45bcb0c9ba2424dacf85e0222aee735f411

pySim/transport/serial.py

@@ -21,10 +21,11 @@ import os
 import argparse
 from typing import Optional
 import serial
+from osmocom.utils import h2b, b2h, Hexstr
 
 from pySim.exceptions import NoCardError, ProtocolError
 from pySim.transport import LinkBase
-from pySim.utils import h2b, b2h, Hexstr, ResTuple
+from pySim.utils import ResTuple
 
 
 class SerialSimLink(LinkBase):