Add ROS_ROOT configuration for cross-compilation

Add ROS_ROOT argument to compose.yaml, update toolchain CMake to search
in ROS_ROOT, and modify final stage of Dockerfiles to copy to ROS_ROOT
instead of TARGET_SYSROOT. Also add support for ROS2 lyrical distro.

cross_compile/ros2/jazzy/ros_jazzy.Dockerfile

@@ -92,4 +92,7 @@ RUN rm -rf ${TARGET_SYSROOT}/opt
 
 FROM ${CC_PLATFORM_IMAGE} AS final
 
-COPY --from=rmw_zenoh_builder ${TARGET_SYSROOT} ${TARGET_SYSROOT}
+ARG ROS_ROOT
+ENV ROS_ROOT=${ROS_ROOT}
+COPY --from=rmw_zenoh_builder ${TARGET_SYSROOT} ${ROS_ROOT}
+WORKDIR /opt