WAL overwrites across clusters with same name

The in-tree barman archiver prevents you from archiving wal files if the object stores already has wals in there generated by a different cluster with the same name.

The plugin instead allows doesn't have this protection and allows to overwrite the files, so there could be wal files from different sources.

首先将 plugin 的归档行为与树内的 barman archiver 进行比较，然后使用来自另一个同名 cluster 的现有 WAL 重现该情况。当 plugin 拒绝覆盖来自不同源的 WAL 文件，并且有测试覆盖该保护机制时，此更改就完成了。

由索引模型根据 Issue 内容生成。