Customize list view for individual entries in nested collections

**Is your feature request related to a problem? Please describe.**
I have a nested folder collection for a directory tree that also includes a news section. For this section (that works like a blog), I want to use a different format for the list view because here the post date is a vital criteria that should appear in the entry summary and in the sort dropdown. But Netlify currently only lets me configure the whole collection.

**Describe the solution you'd like**
In the nested section, I'd like the ability to define a summary that only applies to specific entries/paths:

`config.yml`
```
sortable_fields: ["weight", "title", "commit_date"]
[...]
nested:
depth: 10
summary: '{{title}}'
entries:
- match: 'news'
summary: '{{date}} - {{title}}'
sortable_fields: ["date", "title", "commit_date"]
```

**Describe alternatives you've considered**
An (inferior) alternative would be to provide exclusion filters to be able to exclude entries from the collection. This way, one could achieve the desired presentation for specific entries with a different collection without duplicating the entry. But this breaks the hierarchical structure.