Migrate structural

[jginternational]

Another one I can not run @rubenzorrilla

structure_as_geometry.gid.zip

[jginternational]

Depends on #985

[rubenzorrilla]

structure_as_geometry.gid.zip

To make it work, I added:

• properties 1 to the mdpa
• assigning the properties to the entire model part so the conditions also have properties (hacky, as I conditions should have different properties than the elements)

[rubenzorrilla]

structure_as_geometry.gid.zip

I'd do something like this

• there are no properties in the mdpa
• we assign the "fake" 0 properties to the conditions in the StructuralMaterials.json (we can hardcode this for the moment)

[rubenzorrilla]

Indeed, al these issues come from the fact that our gid_output_process.py maps our properties to output layers. Rather than adding fake properties to the materials json, I think we'd better amend the output stuff.