Feature request - smart views

## Feature request

**Which Nextcloud Version are you currently using:** (see administration page)
28.7.0

**Is your feature request related to a problem? Please describe.**
No it is not

**Describe the solution you'd like**
I'd like to see "smart views". Basically, create a filter and save it as a view. Display only the articles meeting the filter criteria. Ex: only show articles which have "google" in the article or title.

**Describe alternatives you've considered**
Manually filtering every time

**Additional context**

The issue names no files, tests, or entry points. Start by locating the current article-filtering UI in the Android client and determine how a saved filter should become a view; done means a user can save a filter and display only matching articles, including the “google” example.

Written by the indexing model from the issue text.