Revert "Move the setting for "Confirm registration" into institution settings"

This reverts commit a1854f018e7f3b75bbaa2dcaeaad24a38fcd3594.

Bug 1280882: It shouldn't be backported to 1.9_STABLE because it's not a bug fix, and it changes the user interface.

Change-Id: Ib3da16f75f863734e7876c0ffdf3f6e9099c65b9