Make multiple `@External` more ergonomic

[SentryMan]

I think we can all agree that stuff like

@Singleton
public class ProxyModuleRoot {
    @Inject
    public ProxyModuleRoot(
        @External ProxyPlugin proxyPlugin,
        @External ProxyServer proxyServer,
        @External RemoteActionController remoteActionController,
        @External CommunicationProtocol communicationProtocol,
        @External Gson gson,
        @External GlobalPlayerStateController globalPlayerStateController,
        @External SecretsConfig secretsConfig,
        @External @Named("serverIdentifier") String serverIdentifier
    ) { }
}

is not very cash money.

I'm thinking we could make it so that if you annotate a constructor with @external, all the parameters become external