General Desciption:
Fix and enhancements during Mapping config creation

Detailed Description:
* This patch will fix an issue where Mapping config is created even without selecting a KEY or
INCLUDE field from the selection.
* This patch will also cover another known issue where a Mapping source with no "Source fields"
defined can be used as Mapping source for a certain Mapping config, which soon causes page rendering
error (which is why it is highly recommended to install this patch).
* This patch also includes layout enhancements during Mapping config creation.