Use osmocom.construct.{Bytes,GreedyBytes} for hexstring input support

The upstream construct.{Bytes,GreedyBytes} only support bytes/bytearray
input data for the encoder, while the [newly-created]
osmocom.construct.{Bytes,GreedyBytes} support alternatively hex-string input.

This is important in the context of encoding construct-based types from
JSON, where our osmocom.utils.JsonEncoder will automatically convert any
bytes to hex-string, while re-encoding those hex-strings will fail prior
to this patch.

Change-Id: I1c8df6350c68aa408ec96ff6cd1e405ceb1a4fbb
Closes: OS#6774

setup.py

@@ -25,7 +25,7 @@ setup(
         "jsonpath-ng",
         "construct >= 2.10.70",
         "bidict",
-        "pyosmocom >= 0.0.8",
+        "pyosmocom >= 0.0.9",
         "pyyaml >= 5.1",
         "termcolor",
         "colorlog",