ROS2 Migration

[amock]

This repository needs to be migrated to ROS2. I expect to have time for this starting in April/May. If anyone gets to it sooner, please comment here to avoid duplicate efforts.

[amock]

I've pushed the first attempt at migrating this to ROS 2 to the humble branch. In theory, it should work similarly to the ROS 1 version. However, we still need to verify this, and there are a few remaining ROS 2–specific issues:

1. Test a few scenarios to check whether the results match those of the ROS 1 version.
2. A slow TF rate between the map and odom frames causes delayed or missing point cloud rendering in RViz (when using the map frame). How can we fix this?
3. Rendering the TSDF map in RViz2 consumes a lot of GPU resources. Check whether this was also the case in the ROS 1 version.
4. Run more tests.

Once these issues are resolved, we can begin duplicating the branch for Jazzy, as it also compiles and runs there without changes. We can also add more example configurations at that point.