Add database file size and reorganize status page

- Add database file size tracking to Stats struct and GetStats()
- Move routing table metrics to separate 'Routing Table' status box
- Add IPv4/IPv6 updates per second to routing table metrics
- Database box now shows: ASNs, prefixes, peerings, and database size
- Routing table box shows: live routes, IPv4/IPv6 counts, and update rates

internal/database/interface.go

@@ -6,11 +6,12 @@ import (
 
 // Stats contains database statistics
 type Stats struct {
-	ASNs         int
-	Prefixes     int
-	IPv4Prefixes int
-	IPv6Prefixes int
-	Peerings     int
+	ASNs          int
+	Prefixes      int
+	IPv4Prefixes  int
+	IPv6Prefixes  int
+	Peerings      int
+	FileSizeBytes int64
 }
 
 // Store defines the interface for database operations