Update portkey to include portID

[seantking]

Summary of Issue

We need to ensure that new ports that get bound are all stored under unique keys so they can be correctly exported/imported for genesis. We can achieve this by updating the portID mapping key to use portKey + portID instead of just the portKey.

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For Admin Use

• Not duplicate issue
• Appropriate labels applied
• Appropriate contributors tagged/assigned

[damiannolan]

Closed by #467

[gjermundgaraba]

This issue was mistakenly reopened during some integration work, so closing again now.