support post_asset_folder config

# hexo config

[https://hexo.io/docs/configuration.htmll#Writing](https://hexo.io/docs/configuration.htmll#Writing)

```
post_asset_folder: true
```

`New Post` create same name asset folder, thanks.

Start with the Hexo configuration documentation linked in the issue, then trace the New Post flow in the admin interface. Confirm how post_asset_folder is read and where a new post is created; the work is done when enabling it creates an asset folder with the same name as the post.

Written by the indexing model from the issue text.