Handle case where objectscript.conn.docker-compose is being used to deal with dynamic host port

[gjsjohnmurray]

When using vscode-objectscript in its client-side editing mode and compiling/testing/debugging on a container instance of IRIS, it is common practice for docker-compose.yml not to specify the host port that corresponds to the IRIS web server port.

To handle such situations the objectscript.conn configuration object includes a docker-compose structure with which to configure automatic discovery of the dynamically-assigned host port.

Consider enhancing Server Manager to work better for such connections, offering a node under the "Current" tree for each distinct server that the (potentially multi-root) workspace connects to.