Should allow users to tweak all settings.

Plan is to use the HttpServerOptionsConverter (and inherited converters) – perhaps create an extended class and use @DataObject(generateConverter = true, inheritConverter=true) for convenience.

• Ideally need some documentation generation (or perhaps links) so users know which options are available.

• The config should probably go into the specific verticle's config section (only used for port and number of verticles so far), which will may turn require a slight re-org of config. Backwards compatibility could be maintained, I think.

See: HttpServerOptionsConverter, NetServerOptionsConverter, etc