Refactor: move user-related metadata types to common-meta-app/user/

[drmingdrmer]

common/meta/types is by design a container of datatypes that are required only by metasrv, in future.

Data types that are used only by the meta-client side should be kept in another crate:
common/meta/app.

TODO:

• Move data types for user such as common/meta/types/src/user_*.rs to common/meta/app/src/user/