Resolve "enh(viz): shorten scene3d layer configuration"

Description

• The parsing of the 3D scene configuration has been revised as described in #975 (closed).
• Adapted adaptors configuration code to support the absence of any attribute (there was always, at least, the layer attribute)
• Ported all existing configurations to the new scheme (that was ofc not mandatory since we still support the old system)

Closes #975 (closed)

How to test it?

• CI Tests should be enough
• Manual test of any application, ported or not to the new parsing scheme.