LibraryMapping.components is a list that holds the sub-components of a
CMake package. Before, we held this information in
LibraryMapping.extra as find_package argument.
A subsequent patch will make use of LibraryMapping.components and
doesn't have to do find_package argument parsing.
Change-Id: Ie0d317245fb6ec1511e06b2e14c364292fced63a
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>