Better 'makeproductgroups' handling.

* Do not insert group into all products by default when 'makeproductgroups' is on
* Allow to choose whether to create access group for new products
* Move group and series creation calls away from Product->create
* Change help text
* Enable makeproductgroups by default again
WIP: Localisation layer for Bugzilla.

Includes a script for translating TT templates, "false positive" blacklist
and template adjustments for more correct string extraction.