[Feature] Field Mappings support for stored procedure.

[rohkhann]

We need a way to provide mappings for result set of a stored procedure. If a stored procedure for example returns columns that do not meet restrictions in graphql (Example: they have restricted characters, reserved graphql names etc) this would lead to the result being unable to be processed by the hotchocolate server. This issue is for tracking field mappings support for stored procedures.

[ehalsey]

I'm running in to an issue where DAB isn't correctly detecting the return columns of a stored proc. If I strip everything out except the last select statement it works. I suppose I can figure out a workaround e.g. updating the sproc before and after DAB starts but it's not a robust solution.

sorry workaround failed!