Create structs carrying the data of individual VFS functions, and hand those over to the send function, which then casts the void pointer to the struct required by looking at the id. This allows us to return different result data depending on the VFS function that is running. Make the protocol v1 sender compatible to this. Adapt the existing VFS functions to use the new data structures. Make use of the new functionality and extend the mkdir VFS logger function to return the creation mode additionally.
