Extend objectscript.conn.docker-compose settings object to handle superserver port identification

[gjsjohnmurray]

The optional objectscript.conn.docker-compose object allows a VS Code workspace to connect to a local IRIS container instance for which the port serving the /api/atelier API outside the container is assigned dynamically at container startup rather than being hardcoded in the docker-compose.yml

The vscode-iris-jupyter-server extension uses the Node Native API, so the connection has to be to the superserver port.

Let's extend this mechanism so it can look up the assigned superserver port and provide it in the connection object. Server Manager has already acquired the ability for superserver port (and host) to be defined (see intersystems-community/intersystems-servermanager#200) but this doesn't help in the dynamic situation.