Maint: hardcoded data in JSON embedded file

- Server information, versions and timestamps together in internal/constants/servers.json
- breaking change: updater cli uses -enduser instead of -file
- breaking change: updater cli uses -maintainer instead of -stdout
- Fix: replace special last a character with 'a' from Bogota for PrivateVPN
- Feat: do not write out servers and timestamp if no change was detected

internal/updater/providers/cyberghost/string.go

@@ -1,15 +0,0 @@
-package cyberghost
-
-import "github.com/qdm12/gluetun/internal/models"
-
-// Stringify converts servers to code string format.
-func Stringify(servers []models.CyberghostServer) (s string) {
-	s = "func CyberghostServers() []models.CyberghostServer {\n"
-	s += "	return []models.CyberghostServer{\n"
-	for _, server := range servers {
-		s += "		" + server.String() + ",\n"
-	}
-	s += "	}\n"
-	s += "}"
-	return s
-}