[#407] Updating LGSVL volume to official 2020.03 release.

Closes #407 (closed)

Documented issues which appear to be unrelated to this release:

• The AutonomouStuff map produces topics inconsistently. This seems to be partly map-specific but is also very much related to #365 (closed) and other system utilization problems, which are also present on earlier versions. These will be addressed separately.
• Object detection is inoperable. This is due to #419 (closed) and unrelated to this issue.
• The point cloud map cannot be displayed because a map->odom transform is not available until NDT is working/merged in !262 (merged).