Unify ospo-actions configuration

Currently, the various ospo actions are completely independent. But users who adopt several of them end up restating a lot of configuration for them which would ideally be centralized. As concrete examples, setting:

* a list of repositories to ignore from reporting, or conversely a list of ones to _only_ report
* whether to execute in dry run mode or not
* output formats / destinations that are not the default
* ... probably others ...

would be better served by a common configuration file that all of the actions know to look for.

首先，列出現有的 ospo actions，並了解每個 action 目前如何接收設定；issue 中沒有指定任何檔案或進入點。比較它們對遭忽略或納入的 repository、dry-run 模式，以及輸出格式或目的地的處理方式。當這些 actions 能夠使用共用設定來源而不必重複這些設定時，即表示完成。

由索引模型根據 Issue 內容生成。