Export external dependencies in FCL_LIBRARIES

The find_package CMake macro was missing the CCD and Octomap libraries
in the FCL_LIBRARIES variable, which led to linker errors in dependent
projects, for example:

moveit/moveit#2804 (comment)

The old PkgConfig implementation properly adds all external
dependencies, but the find_package implementation is missing some:

find_package: FCL_LIBRARIES=fcl
PkgConfig:    FCL_LIBRARIES=/opt/ros/noetic/lib/x86_64-linux-gnu/libfcl.so;/usr/lib/x86_64-linux-gnu/libccd.so;/usr/lib/x86_64-linux-gnu/libm.so;/opt/ros/noetic/lib/liboctomap.so;/opt/ros/noetic/lib/liboctomath.so

This commit will result in the following FCL_LIBRARIES:
FCL_LIBRARIES=fcl;/usr/lib/x86_64-linux-gnu/libccd.so;/usr/lib/x86_64-linux-gnu/libm.so;/opt/ros/noetic/lib/liboctomap.so;/opt/ros/noetic/lib/liboctomath.so

fcl-config.cmake.in

@@ -6,7 +6,7 @@ set(FCL_VERSION "@FCL_VERSION@")
 set(FCL_ABI_VERSION "@FCL_ABI_VERSION@")
 
 set_and_check(FCL_INCLUDE_DIRS "@PACKAGE_CMAKE_INSTALL_INCLUDEDIR@")
-set(FCL_LIBRARIES @PROJECT_NAME@)
+set(FCL_LIBRARIES @PROJECT_NAME@ @CCD_LIBRARIES@ @OCTOMAP_LIBRARIES@)
 set_and_check(FCL_LIBRARY_DIRS "@PACKAGE_CMAKE_INSTALL_LIBDIR@")
 
 include(CMakeFindDependencyMacro)