Implement filters to suppress junk in app store

## Feature requests
1. Add filter for minimum "Highest Nextcloud version"
2. Add filter for minimum "Last updated"
3. Tag apps "junk status" if they are "last updated" over 1 year ago OR "Highest NC version" is current minus two. Add filter "Suppress junk status apps" (default: active)

**Is your feature request related to a problem? Please describe.**
I am new to Nextcloud, now migrating from Microsoft.
I need a backup for my data and entered "backup" in the app store search.
Result: Only 3 apps, and two of them say "Use this app at your own risk! Data loss may occur! Last updated
6 years, 11 months ago" (Ownbackup, Nextbackup). List of results shows 17 irrelevant apps.
Market trust in general depends on a professional first impression. This is destroys Nextcloud market reputation and chances.

**Describe the solution you'd like**
Implement the feature requests, so that either quality apps can be found or authors jump in to create them.

**Describe alternatives you've considered**
Tell my contacts that Nextcloud is still unprofessional.

**Additional context**

Start by locating the app-store search and result-filtering entry points, then trace where “Highest Nextcloud version” and “Last updated” metadata are handled. Done means minimum-version and minimum-date filters work, stale apps receive the requested junk status, and junk suppression is enabled by default.

Written by the indexing model from the issue text.