Support IdGenerator and VersionGenerator in backend (Support ULID, Snowflake, etc.) #125
Description
Each repository has a mechanism for generating an Id and Version property should these not be maintained by the backend data store. In order to support ULID and Snowflake IDs, these need to be altered.
This is not a problem within the client side since the user specifies the Id of the created entity (or sets it to null) and - if null - the server sets the ID.
Affects EntityTableRepository, InMemoryRepository, and LiteDbRepository.