Allow to restrict number of connections

[fhg-isi]

• [x ] I agree to follow the Code of Conduct that this project adheres to.
• [x ] I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Is your feature request related to a problem? Please describe.

I would like to restrict the number of allowed connections for elements.
For example my "source" element should only allow one connection.

Describe the solution you'd like
Implement a property numberOfAllowedConnections to restrict the number of possible connections.

Describe alternatives you've considered
I manually created a single connection point and enabled snapping.
Its still possible to add extra connections at arbitrary positions.

Additional context

Also see
https://stackoverflow.com/questions/79270946/how-to-limit-the-number-of-connections-for-a-shape-in-draw-io-app-diagrams-net