Revamp nav2_util CMakeLists.txt to use modern idioms. (ros-navigation…

…#4393)

This commit does a number of things:

1.  Switches to using target_link_libraries everywhere.
This gives us finer-grained control over what dependencies
are exported to downstream as public, or private.  In the
particular case of nav2_util, this actually doesn't matter
*too* much, but it will help for other packages.
2.  Moves the include directory down one level to
include/${PROJECT_NAME}, which is best practice in ROS 2
since Humble.
3.  Makes sure to export nav2_util as a CMake target, so
downstream users of it can use that target.
4.  Moves the base_footprint_publisher.hpp header file into
the src directory, as it isn't functionality that an external
project could use.

Signed-off-by: Chris Lalancette <[email protected]>

nav2_util/src/base_footprint_publisher.cpp

@@ -14,7 +14,7 @@
 
 #include <memory>
 
-#include "nav2_util/base_footprint_publisher.hpp"
+#include "base_footprint_publisher.hpp"
 
 int main(int argc, char ** argv)
 {

nav2_util/test/test_base_footprint_publisher.cpp

@@ -15,7 +15,7 @@
 #include <string>
 #include <memory>
 
-#include "nav2_util/base_footprint_publisher.hpp"
+#include "base_footprint_publisher.hpp"
 #include "gtest/gtest.h"
 #include "tf2/exceptions.h"