Material properties chapter number missing in nav

[ClemensLinnhoff]

Describe the bug
The number of the material properties chapter is missing
This is probably because the name is manually changed in the nav file. It would be better to change this in the asciidoc generation from the schema files. Then we don't need the manual naming in the nav anymore.

Expected behavior
Show the correct chapter number in the nav bar

Screenshots

[ClemensLinnhoff]

We should discuss the general structure of describing the file formats of asset files, material files, emp material files and brdf material files.

Currently we have a section for the metadata respectively for geometry and material. And we have sections for material properties and lookup tables:

• 7 Geometry
  • ...
  • 7.4 File format
  • 7.5 Metadata
  • (7.6 Material mapping?)
• 8 Material
  • ...
  • 8.2 File format
  • 8.3 Metadata
  • 8.4 Material properties
  • 8.5 Lookup tables
    • 8.5.1 Electromagnetic properties

Do we want to keep it this way or change to a structuring per file?

• 7 Geometry
  • ...
  • 7.4 Asset file
    • 7.4.1 metadata
    • 7.4.2 materialMappingUri
  • 7.5 Material mapping file
    • 7.5.1 metadata
    • 7.5.2 materialMapping
• 8 Material
  • ...
  • 8.2 Material file
    • 8.2.1 metadata
    • 8.2.2 materialProperties
  • 8.3 Electromagnetic properties
    • 8.3.1 metadata
    • 8.3.2 electromagneticProperties
  • 8.4 Brdf lookup table
    • 8.4.1 metadata
    • 8.4.2 brdf

In my opinion the second option is more structured and describes more clearly the different file formats. But we have to think about the metadata. Does each file have its own definition or do for example all material files have the same metadata definition? If the latter is the case, then we would introduce some redundancy to the documentation.