Use LocatePythonModule to find make-dissector-reg.py in order to make UseMakeDissectorReg.cmake more generally (out-of-source) usable.
Add make-dissector-reg.py to the Debian packages.

Making it possible to generate out-of-source wireshark plugins.

Change-Id: I0bbe5b46205d39e229d31812341540b26a7336d6
Reviewed-on: https://code.wireshark.org/review/5802
Reviewed-by: Anders Broman <a.broman58@gmail.com>