[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.

從 CloudStack Management 的安裝流程、management UI 登入以及 /etc/cloudstack/management/key 中的資料庫金鑰開始。追蹤預設管理員密碼和加密金鑰在哪裡建立及使用。完成的標準是：兩個值都在執行前從可靠的熵中產生，不存在可使用的預設值，並且安裝行為有測試涵蓋。

由索引模型根據 Issue 內容生成。