Add global model reference to ground truth

[pmai]

This PR represents a PR from the SETLevel4To5 project, adding an optional model_reference to the top-level ground truth, to allow the specification of a 3D model representing the environment: This model covers the static parts of the environment that are not provided as individual models referenced from ground truth objects like moving or stationary objects. It is implementation-specific which exact parts this world model contains, e.g. whether it contains street geometries, or whether those are derived automatically from a map reference, if one is provided.

Signed-off-by: Pierre R. Mai [email protected]

• My code and comments follow the style guidelines and contributors guidelines of this project.
• I have performed a self-review of my own code.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests / travis ci pass locally with my changes.

[kmeids]

Output from CCB meeting - 25.11.2020

Actions:
@paagkame to review the documentation under "Files changed".

[paagkame]

documentation review is done. Please have a look at the changes.

[kmeids]

Output from CCB meeting - 09.12.2020
Actions:

1. Pull request to be merged by @pmai