add `minMonthlyDownloads` filter for Trending, a11y fixes

[Simek]

📝 Why & how

I have noticed that low download penalty does not work ideally after the popularity gain scoring has been tweaks, so I have decided to add a new query filter field minMonthlyDownloads which will filter out the libraries with less than specified download count in last month.

Additionally, I have made few a11y related tweaks and fixes.

✅ Checklist

• [ ] Added library to react-native-libraries.json
• [ ] Updated library in react-native-libraries.json

• [ ] Documented in this PR how to use the feature or replicate the bug.
• [x] Documented in this PR how you fixed or created the feature.