[tools] add script to automatically generate bacnet vendors

Requires beautifulsoup4 for parsing, translitcodec for converting accents/diaeresis etc to regular text

Change-Id: I4d400f15916ee3ab07fa14b09fca12beac2010f3
Reviewed-on: https://code.wireshark.org/review/4518
Reviewed-by: Evan Huus <eapache@gmail.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>