The segmentation should be X**Z**. This is because of how the trd is constructed (with z along the normal y direction).

 - using "athena"
 - this avoids any clashing with the reference detector libraries.

 - Looks like some overlap issue with the face endcap layers and the
 barrel layers' end-face .

Paying attention to following items:
* Overall parameterization -- will use for optimization
* Constant naming consistency
* Documentation via the comments
* Added new ci job which concatenates all the `<comment>` tags into `docs/detector.md`
* All comments should now be formatted to fit the appropriate section in the markdown file.

- The outer tracker barrel's 2 layers are commented out
- The subsystem is then properly constructed in the acts geometry
- There is probably a small bug in this part of the barrel which is
inconsistent with the way ACTS constructs its tracking geometry

The ACTS layers cannot have overlapping surfaces.
This will likely go away in future when the concept of "layers" is
removed from ACTS geometry.

- Renamed the vertex and tracker barrel detectors
- Commented out endcap tracker
- Added more detailed to space frame construction.