Add more utils

[sveneberth]

• resolveDictPath resolve_dict_path feat: Implement resolve_nested_path #54
• has_truthy_value
• UserContext
• normalize_umlauts
• ensure_translation feat: Implement ensure_translation #55
• (flat) copy_skel
• is_subskel https://github.com/viur-framework/viur-shop/blob/f56826313f7c231added0b31a4ad20b3571f9cba/src/viur/shop/types/dc_scope.py#L243-L257