COMP: Find LibArchive/CURL/OpenIGTLink/ZLIB package where required.

This commit complements commit r23350 and will help reducing the number
of parameters passed to the compiler/linker. See #3741

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23355 3bd1e089-480b-0410-8dfb-8563597acbee
COMP: Find qRestAPI package only where required.

This commits moved the discovery of the qRestAPI module in both QTCore
library and DataStore remote module.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23356 3bd1e089-480b-0410-8dfb-8563597acbee