Create Invenio-I18N blueprint.

def create_blueprint(register_default_routes=True):
    """Create Invenio-I18N blueprint."""
    blueprint = Blueprint(
        'invenio_i18n',
        __name__,
        template_folder='templates',
        static_folder='static',
    )

    if register_default_routes:
        blueprint.add_url_rule('/', view_func=set_lang, methods=['POST'])
        blueprint.add_url_rule('/<lang_code>', view_func=set_lang,
                               methods=['GET'])

    return blueprint