Lyrical Nav2;-)

[Marco Walther]

OK, I got the complete Nav2 (main branch) and slam_toolbox (prerequisite
for Nav2, ros2 branch) sources built on Ubuntu 26.04 on a Pi5 and a
x86-64 VirtualBox;-)

* On the Pi5, rviz2 & gazebo come up via X11 forwarding for the little
'getting started' exercise, but then the Pi5 freezes:-( I guess, 8GB is
not really enough for that. I'll switch that to a 'more real' Sawppy;-)

* On the VBox, the simulation works as expected;-)

* I'm running Lyrical from ros2-testing, the released package set is
still missing at least the ros-lyrical-ompl package:-(

* I had to make some changes, even to installed ROS & system packages:-(

** https://github.com/ros2/rcl_interfaces/issues/201
** A similar change in `sudo vi +1394 /usr/include/gtest/gtest.h`
** `ubuntu@ubuntu-2604-lyrical:/opt/ros/lyrical/lib$ sudo ln -s
x86_64-linux-gnu/libbehaviortree_cpp.so .` or the equivalent for the
aarch64;-)

I'll attach a little video ( https://photos.app.goo.gl/rDBmGF4Yx7un1p5n6
) and my diffs (many cmake minimum version changes, few others)

Have fun;-)
-- Marco