Handle Model Composition in Swagger Parser

Swagger 2.0 uses allOf property to handle model composition.
e.g
[BillingSubscription](https://github.com/Azure/azure-rest-api-specs-pr/blob/53dffd5cd0a04e5ca44622a8bd84b2ce762bb578/specification/billing/resource-manager/Microsoft.Billing/preview/2022-10-01-privatepreview/billingSubscription.json#L1476C1-L1481C58) is a [ArmResource](https://github.com/Azure/azure-rest-api-specs-pr/blob/53dffd5cd0a04e5ca44622a8bd84b2ce762bb578/specification/billing/resource-manager/Microsoft.Billing/preview/2022-10-01-privatepreview/types.json#L189C1-L194C106) which in turn is a [Resource](https://github.com/Azure/azure-rest-api-specs-pr/blob/53dffd5cd0a04e5ca44622a8bd84b2ce762bb578/specification/common-types/resource-management/v3/types.json#L9C5-L9C8)

APIView should have a way of showing that relationship.

Start by examining the Swagger 2.0 allOf examples linked in the issue, including BillingSubscription, ArmResource, and Resource, and trace how APIView currently parses or displays model relationships. The work is complete when APIView visibly represents the composition chain described by those schemas; the issue does not name implementation files or tests.

Written by the indexing model from the issue text.