[Feature]: Implement FlowExtensions

[samatstariongroup]

Prerequisites

• I have written a descriptive issue title
• I have verified that I am running the latest version of the SysML2.NET
• I have searched open and closed issues to ensure it has not already been reported

Description

The FlowExtensions class in SysML2.NET/Extend/FlowExtensions.cs contains 6 extension method(s) that compute derived properties for the IFlow interface. These methods currently throw NotSupportedException and need to be implemented.

Checklist

• List<IFlowEnd> ComputeFlowEnd(this IFlow)
• List<IInteraction> ComputeInteraction(this IFlow)
• IPayloadFeature ComputePayloadFeature(this IFlow)
• List<IClassifier> ComputePayloadType(this IFlow)
• IFeature ComputeSourceOutputFeature(this IFlow)
• IFeature ComputeTargetInputFeature(this IFlow)

System Configuration

• SysML2.NET version: 0.19.0
• Source file: SysML2.NET/Extend/FlowExtensions.cs