Generate a smaller Bugzilla component .json file

Fix issue #140 

Current situation: php generates the web/cache/bugzilla_components.json file if missing or older than a week, current size 9.5MB

Solution:
* move generation of this file to a python script (bugzilla_query.py) and call it at the end of glossaire.sh if the file is missing or older than a week
* strip the file from all unnecessary information, but maintain the same structure of the original. If for any reasons the file is missing, php can still generate the gigantic file

Resulting file: 3 kB

I've also remove web/bugzilla_components.txt since I can't find any reference in the code.