UI : Show the Backup repository as column in Backup offerings view

### The required feature described as a wish

Currently, if there are multiple back up repository in Cloudstack

Its difficult to identify the backup offerings associated with the backup repository from the UI.

Expected behaviour

It would be great if the backup column is added to the backup offerings view

also the backup repoistory is mentioned as External id (uuid) it would be great if the backup reposistory name is mentioned

https://cloudstack.apache.org/api/apidocs-4.22/apis/listBackupRepositories.html
https://cloudstack.apache.org/api/apidocs-4.22/apis/listBackupOfferings.html

先查看 issue 中連結的 listBackupRepositories 和 listBackupOfferings API 文件，接著找到 Backup Offerings 檢視，並確認其目前的儲存庫識別碼是如何填入的。對於與多個儲存庫相關聯的 offerings，如果該檢視顯示包含儲存庫名稱的備份儲存庫欄位，而不只是其外部 ID，即表示完成。

由索引模型根據 Issue 內容生成。