Add new functions for app-defined loader feature

Add new functions for app-defined loader feature

Adds:
 - aul_prepare_app_defined_loader()
 - aul_prepare_app_defined_loader_for_uid()

Requires:
 - https://review.tizen.org/gerrit/#/c/platform/core/appfw/aul-1/+/224466/
 - https://review.tizen.org/gerrit/#/c/platform/core/appfw/amd/+/224634/
 - https://review.tizen.org/gerrit/#/c/platform/core/api/app-control/+/224798/
 - https://review.tizen.org/gerrit/#/c/platform/core/appfw/launchpad/+/224161/

Change-Id: I1d49468985fa04c0dd6a3d70a45347d4ffecc0a4
Signed-off-by: Hwankyu Jhun <h.jhun@samsung.com>