chore(updater): common GetServers signature

- Log warnings when running outside of CLI mode
- Remove updater CLI bool setting
- Warnings are logged in updating functions

internal/provider/cyberghost/updater/updater.go

@@ -0,0 +1,13 @@
+package cyberghost
+
+import "github.com/qdm12/gluetun/internal/updater/resolver"
+
+type Updater struct {
+	presolver resolver.Parallel
+}
+
+func New(presolver resolver.Parallel) *Updater {
+	return &Updater{
+		presolver: presolver,
+	}
+}