Maint: remove NordVPN SERVER_NAME filter

- Filter was not effective
- Is to be deprecated in v4 anyway
- Bump NordVPN server model version to `3`
- Remove `Name` field from NordVPN server model

internal/models/server.go

@@ -65,7 +65,6 @@ type MullvadServer struct {
 type NordvpnServer struct { //nolint:maligned
 	Region   string `json:"region"`
 	Hostname string `json:"hostname"`
-	Name     string `json:"name"`
 	Number   uint16 `json:"number"`
 	IP       net.IP `json:"ip"`
 	TCP      bool   `json:"tcp"`