[Hardening] F-02: Default Configuration Forces User’s Posture to Password-Only.

### The required feature described as a wish

**Description:** the global configuration setting `enable.user.2fa` defaults to False, meaning users who wish to use two-factor authentication (2FA) cannot do so without a Root Admin first enabling the setting and restarting the management server(s).

**Affected Components:** Management UI

**Impact:** Any compromised or weak user credential is sufficient to gain full access to a user's CloudStack account. This makes the platform susceptible to credential-stuffing, phishing, and brute-force attacks with no second factor to impede unauthorized access.

**Steps to Reproduce:**
- Log in to the CloudStack Management UI as a Root Admin.
- Navigate to Configuration > Global Settings.
- Search for `enable.user.2fa` and observe that its value is set to False.
- Attempt to enable 2FA on your own user account, and confirm that it is not permitted.

**Recommended Remediation:** Change the default value of `enable.user.2fa` to True so that users are always permitted to enroll in 2FA without requiring Root Admin intervention.

Inizia dalla gestione di enable.user.2fa nella Management UI, in Global Settings, e verifica in che modo il suo valore predefinito controlla la registrazione degli utenti. La modifica è completata quando il valore predefinito consente agli utenti di registrarsi a 2FA senza l’intervento di un Root Admin o il riavvio del management-server; conferma l’impostazione e il flusso di registrazione nella UI.

Scritto dal modello di indicizzazione a partire dal testo della issue.