Moves the Nova-facing resources and metrics (AnalyticsVisit, PageviewsTrend, TopTrafficSources) out to a new companion package, sergeybruhin/nova-analytics. This package now stays dependency-light and installable without a Nova licence, mirroring the laravel-postgres-tools / nova-postgres-tools split. Adds sessions()/pageviews()/events() relations on Visitor and pageviews()/events() on Session so the new Nova package's HasMany fields resolve.