Apply baseURI to list of things generated by HTTP server

Setting the baseURI in the configuration of an HTTP server currently changes the forms for all interaction affordances, but does not apply to the list of Things exposed by the server (https://github.com/eclipse/thingweb.node-wot/blob/master/packages/binding-http/src/http-server.ts#L694).

Not sure whether this is intended or not, but because the baseURI configuration is separate from base in the Thing Description, I thought it might be worth having baseURI applied consistently. This also avoids leaking local IP addresses if a node-wot server is exposed to the Internet through port forwarding, which was my use case.

If this is worth fixing/merging, I'll open a pull request.