Update method on schema level instead of query level.

[Juriaan-007]

For a dataflow gen2 you can specify a default update method for a destination. This is set to append. This can only be changed by specifying a uplade method of replace for every single query. This involves alot of work when dealing with large schema and alot of tables. I would like to have the option for a update method for the default destination. (with the option to change this on a later moment)