Handling circa 5% of the router setup guide missing informations

[DandelionSprout]

Inspired by #188, but is not remotely close to fixing that issue report, as these changes should (and honestly speaking must) also be handled on https://adguard-vpn.com/en/blog/adguard-vpn-for-routers.html, for which there's no repo that I can find.

• An initial list of incompatible router brands, for which even recently released routers on newest firmwares doesn't support it (ASUS and FRITZ!Box).
• Specifying that it's not sufficient for a router to simply support IPsec; it must also support it in the VPN client settings specifically.
• Splitting up notes on smart TVs and other smart-devices in the general headers.
• Added mentions of more game consoles; although the section was called "Playstation and Xbox", only "PS4 and PS5" had been listed as individual console models.

[DandelionSprout]

Should be good enough now. 🌞