3D to 2D lidar scan

[Daniel-Martin576]

Goal: Previously, we used a 2D lidar so our mapping stack took in a 2D lidar scan, but now we want to use a 3D lidar. Either add a small node than takes in the 3D lidar scan and thresholds it at a fixed z/height-value or see if our stack can somehow take in a 3D scan to add obstacles (we used costmap_2d). The first option is more likely what is going to end up happening, but you can maybe test the second one.

Files Edited (at least): rr_evgp/src/lidar_z_threshold/lidar_z_threshold.cpp

Success Criteria:

• Node parameters configurable through the launch file
• Can make a 2D map like before using the 3D lidar