Separate the JGroups integration component into a dedicated WildFly feature pack

Since we'll resolve HSEARCH-2598 Closed the feature pack doesn't have to be removed completely, but we might still want to make sure it can be excluded from the main feature pack. Maybe we should ship this as an independent feature pack? The reason being we want to have WildFly build assembling our feature pack, but we don't want to include the JGroups backend in WildFly until it's no longer marked experimental.