Support Dynamic Intent Handler Registrations in the FDC3 for web DA reference implementation

[robmoffat]

Minor Issue

Area of Issue

• [ ] App Directory
• [ ] API
• [ ] Context Data
• [ ] Intents
• [ ] Desktop Agent Bridging
• [ ] Use Cases
• [x] Other

Issue Description:

From:

• #1594

• The refernce implementation does not support dynamic registration (so if we add an intent listener it will not appear in the app resolution dialog)

• We should add support for dynamic registration to the reference implementation

[Roaders]

Just FYI - I am adding this in #1594