Revert "added LuaSyncedCtrl:SetUnitExperienceScaling(unitID, key, val) to set experience scaling factors per-unit"
Revert "updated changelog"

This reverts commit e2ca598b653b71b14f65a82c595b4b5f0cae8fad &
4c8a3407ecd00b9c5c4db9bf1dd36d3639b7da0a