Re-implement connections (edges) in node graph

Existing feature/capability to improve

A continuation of node graph refactoring to re-implement connections (edges) as needed for opencpi.

Testing requirements

N/A

Define success

Ports between nodes are able to be connected and appropriate connection attributes are able to be set by user.

Links/references

Acceptance criteria

• Ports able to be connected between nodes
• Appropriate connection attributes able to be set
• Able to redirect a connection from one node/port to another node/port