Packaging: macOS relocation of libraries without children

* macOS install path must be <bundle>/MacOS in order for
    QLibrary to find qt.conf to set the correct bundle paths
  * Refactored to add an explicit graph traversal to set the
    dynamic loader id to handle the case where a bundled
    resource does not have any children
  * Fixed the case where rpaths were not removed from
    libraries without children
  * Improved diagnostics when bundling fail to finds
    a dependent library in the search path

Mantis: #0002886
Refs: #535

src/Main/CMakeLists.txt

@@ -49,11 +49,16 @@ if(BUILD_GUI)
             RUNTIME DESTINATION bin
             LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
         )
-    else(WIN32)
+    elseif(APPLE)
+        INSTALL(TARGETS FreeCADMain
+	    RUNTIME DESTINATION MacOS
+            LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+        )
+    else()
         INSTALL(TARGETS FreeCADMain 
             RUNTIME DESTINATION bin
         )
-    endif(WIN32)
+    endif()
 endif(BUILD_GUI)
 ######################## FreeCADMainCmd ########################