Display connection instructions on tty1

[rgaudin]

Uninformed users might try to connect the Host Pi to a monitor for use instead of using the WiFi/eth connection.
We should display a message leading them to the WiFi in the first tty.

Ideally, displaying the AP's SSID (and passphrase?), whether it allows Ethernet connection would be even better but given we don't store those information, that would be significantly more work and code (inspection).

We don't need it at the moment. A static message would be sufficient for now. If the need for more arise, we'll reconsider.

From offspot/kiwix-hotspot#683