chore: add convert bytes to a human-readable string with the appropriate unit (bytes, MiB, or GiB)

templates/email.tmpl

@@ -56,7 +56,7 @@
             <li><strong>Backup End Time:</strong> {{.EndTime}}</li>
             <li><strong>Backup Storage:</strong> {{.Storage}}</li>
             <li><strong>Backup Location:</strong> {{.BackupLocation}}</li>
-            <li><strong>Backup Size:</strong> {{.BackupSize}}  MiB</li>
+            <li><strong>Backup Size:</strong> {{.BackupSize}}</li>
             <li><strong>Backup Reference:</strong> {{.BackupReference}}</li>
         </ul>
     </div>

templates/telegram.tmpl

@@ -10,7 +10,7 @@ Backup Details:
 - Backup EndTime: {{.EndTime}}
 - Backup Storage: {{.Storage}}
 - Backup Location: {{.BackupLocation}}
-- Backup Size: {{.BackupSize}}  MiB
+- Backup Size: {{.BackupSize}}
 - Backup Reference: {{.BackupReference}}
 
 You can access the backup at the specified location if needed.