4.x - named routing

[romain-grecourt]

Description

• Add new .routing variants in WebServerConfig.Builder
• Update LoomServer to use the new named routings
• Update multiport example to use the new API
• Fix multiport example README.md and dependencies (/observe and dependencies)

Fixes #7702

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Documentation

One can now register routing for a named socket created via .config(config.get("server")).

Before:

server.routing(Main::publicRouting)
        // Add a set of routes on the named socket "admin"
        .putSocket("admin", socket -> socket.from(server.sockets().get("admin"))
                .routing(Main::adminSocket))
        // Add a set of routes on the named socket "private"
        .putSocket("private", socket -> socket.from(server.sockets().get("private"))
                .routing(Main::privateSocket));

After:

server.routing(Main::publicRouting)
        .routing("admin", Main::adminSocket)
        .routing("private", Main::privateSocket);

[tomas-langer]

The API looks much better. The only problem I can see is if somebody combines both methods (we may want to warn/throw an exception for such cases).