Deduplicate MassTransit routing slips, activities and consumers

backend/Core/Musify.Application/Contracts/IDatabase.cs

@@ -34,6 +34,8 @@ public interface IDatabase
 
     public Task<IDatabaseTransaction> BeginTransactionAsync(System.Data.IsolationLevel isolationLevel, CancellationToken cancellationToken);
 
+    public DbSet<TEntity> Set<TEntity>() where TEntity : class;
+
     public Task<int> SaveChangesAsync(CancellationToken cancellationToken);
 
     public Task<ErrorOr<Success>> TrySaveChangesAsync(Error onUniqueViolation, CancellationToken cancellationToken);