relationship.py: Remove unused import

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@21181 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
GrampsLocale: Restructure so that multiple GrampsLocale objects can safely be created for different locales

Only the first dependent upon the environment
All may be created with parameters which override environment variables or OS settings.
See the GrampsLocale docstring for details.

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@21182 4ae1f11a-8b86-4847-b8af-ab372f36d1fd