Update FAQ.md

Update FAQ.md

- Mastonaut for macOS is now free, removed cost info and added close source info
- updated name for Mastodon client
- added Whalebird for Windows
- added Mastodon for Android
- removed Dica (last update Jan 2019, developer website, source code github and support forum link on Google Play site dead)
- added Tusky F-Droid and Google Play links
- removed twitlatte (This app was suspended by Twitter. Please use other app. as per repo info)
- Yuito added Google Play link
- Twidere X added F-Droid and Google Play links
- removed Roma (App will be removed from app store on 3/15/2021 and support ended, as per Google Play info)
- removed website links for tooot and b4x ios, twidere android for consistency - app name ideally always goes to source