[CM1-552] Present current user as Case owner at ER case import

As a user I want the case owner dropdown to have my name selected/suggested when I import a case

I shall be able to change to another user as case owner for the imported case if I want

Because this will save me one click if I always import my own cases.

We have added a setting in Admin//General Settings, where you as admin can chose if you want this functionality turned on or off.