GrampsLocale: Reduce circular imports

Lets one import grampslocale directly in a test script:
>>> from gramps.gen.utils.grampslocale import GrampsLocale
>>> import os
>>> gl = GrampsLocale(lang='fr_FR.UTF-8', localedir=os.path.join('build', 'mo'))
>>> tr = gl.get_translation().gettext
>>> tr("List of known family trees in your database path\n")
u'Liste des arbres familiaux connus dans votre chemin de base de donn\xe9es\n'

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@21640 4ae1f11a-8b86-4847-b8af-ab372f36d1fd