Windscribe API and more servers filter options, fixes #197 (#282)

- Use Windscribe API to fetch servers information
- More data on servers about region, city and hostname
- Add optional server filters with `REGION`, `CITY` and `HOSTNAME` csv environment variables

internal/constants/servers.go

@@ -47,8 +47,8 @@ func GetAllServers() (allServers models.AllServers) {
 			Servers:   VyprvpnServers(),
 		},
 		Windscribe: models.WindscribeServers{
-			Version:   1,
-			Timestamp: 1599323261,
+			Version:   2,
+			Timestamp: 1604019438,
 			Servers:   WindscribeServers(),
 		},
 	}