Update Annex UML to include interactions diagrams also

[BirgitBoss]

What?

.interactions diagrams are used in specficiation but they are not explained in Annex.

Especially the "alt" for alternative might need explanation in figure 5 Sequence of Bulk API Operation

• I have signed the required Developer Certificate of Origin (DCO) already.

[sebbader-sap]

Is "alt" not a standard part of UML interaction diagrams? (This is not related to the general observation that the UML section misses the interaction diagrams.)

[sebbader-sap]

I don't see this as a critical finding for 3.1, therefore postponing it.