Update Copy Data Activity to allow for adding columns to multiple tables

Currently custom columns can be added to one table, but when importing multiple tables and needing to add the same columns to every table, this is not possible. Our specific use case is that we are loading multiple tables from our SQL server into a Lakehouse and want to add a Load_Date column and a Pipeline_RunID column to every table that is loaded. When loading one table this is very easy, but when we load more than one table, the current functionality of the mapping tab within the copy data activity does not allow this.