Modified `AddDbRepository` method to allow broader entity types and registered `queryFactory` as a singleton. Added necessary using directives in `DbRepositoryTests.cs` and updated the `Setup` method to configure an in-memory database for testing with `MockDbContext` and `User` entity.
This commit introduces a new `DbRepository` class implementing the `IRepository<TEntity>` interface, providing asynchronous methods for CRUD operations. The previous CRUD repository registration in `DIExtensions.cs` has been removed, indicating a shift in repository management. A new static class `DependencyInjection` has been added to facilitate the registration of `DbRepository` with the service collection, enhancing modularity and flexibility in database interactions.
