Option to not register broker through HippoServiceRegistry

As hst core and crisp core can be deployed onto both site wars and cms/platform war in v13.0.0, we need an option to register or not register the broker service through HippoServiceRegistry.
In earlier versions (2.x), it was always registered, which is a problem if you have multiple site wars.
Therefore, we need an option to explicitly set to register service.
And it should not register a service by default.

If someone wants to register it (in cms/platform war for example), they can set a configuration in hst-config.properties.