[Hardening] F-13: Weak Default Password and Database Encryption Key.

### The required feature described as a wish

**Description:** CloudStack ships with a default administrative password and database encryption key, both set to the string "password". Neither value is randomized at install time, and the administrator is not prompted to change them during setup. Note that the database encryption key cannot be changed afterwards.

**Affected Components:** Management

**Impact:** An attacker with knowledge of the default credentials, which are publicly documented, can authenticate to the CloudStack Management UI without any prior reconnaissance or effort. Additionally, if the database encryption key is not changed, an attacker who gains read access to the database (e.g., via SQL injection, a misconfigured backup, or direct server access) can decrypt all protected fields, including API secret keys, passwords, and other credentials, using the known default key.

**Steps to Reproduce:**
- Deploy a fresh CloudStack instance following the official documentation.
- Attempt to log in using the username `admin` and the password `password`.
- Observe that login succeeds without any prompt to change the default password.
- Separately, inspect the database encryption key on the management server:
- $ cat /etc/cloudstack/management/key
- Observe that the encryption key is set to the default value `password`.

**Recommended Remediation:** Generate a unique password and database encryption key from a reliable source of entropy during installation (before the system becomes operational). Neither value should have a usable default.

从 CloudStack Management 的安装流程、management UI 登录以及 /etc/cloudstack/management/key 中的数据库密钥开始。追踪默认管理员密码和加密密钥在哪里创建和使用。完成的标准是：两个值都在运行前从可靠的熵中生成，不存在可用的默认值，并且安装行为有测试覆盖。

由索引模型根据 Issue 内容生成。