remove Compositon from UML Annex + add Reference Modelling

[BirgitBoss]

Since no aggregated composition is used in the specification but his is modelled as class attribute Figure 7 in https://industrialdigitaltwin.io/aas-specifications/IDTA-01001/v3.1/annex/uml.html#omg-uml-general could be removed.
Same for shared aggregation because a different notation is used: Reference

Alternative: add note, that it is not used and reference https://industrialdigitaltwin.io/aas-specifications/IDTA-01001/v3.1/annex/uml.html#omg-uml-specifics

Same in https://industrialdigitaltwin.io/aas-specifications/IDTA-01001/v3.1/annex/uml.html#omg-uml-specifics Figure 18

see also https://industrialdigitaltwin.io/aas-specifications/IDTA-01001/v3.1/annex/uml-templates.html, here shared aggregation is also still mentioned.

Instead the new way of modelling shared aggregation with type "Reference" shall be described in https://industrialdigitaltwin.io/aas-specifications/IDTA-01002/v3.1.1/annex/uml.html#_notes_to_graphical_uml_representation

[BirgitBoss]

TF Metamodel 2025-08-05

• Explain Reference Representation
• Explanation of shared and composite aggregation may stay since not wrong even if it is not used