Fix: Remove unused datastructure package (#193)

go.mod

go.sum

packages/datastructure/doubly_linked_list.go

packages/datastructure/doubly_linked_list_entry.go

packages/datastructure/doubly_linked_list_test.go

packages/datastructure/errors.go

packages/datastructure/krw_mutex.go

packages/datastructure/krw_mutex_test.go

packages/datastructure/lru_cache.go

packages/datastructure/lru_cache_options.go

packages/datastructure/lru_cache_test.go

packages/datastructure/random_map.go