We need to bring upsert_stage.cpp & update_stage.cpp into mongos for PM-1632. Right now, those files are built as a part of the query_exec library; however, this is a large executable to add to the mongos binary.

On slack, it was mentioned that a concern of including query_exec as is directly in mongos' binary is that it includes a lot of SBE code which is not relevant on mongos.

Two solutions come to mind, either separating update_stage.cpp, upsert_stage.cpp, and all its dependancies into it's own library or separate all SBE code into a separate library, but any approach to reduce the size of the binary imported into mongos would be helpful.