This is a (undocumented) tool for generating printable A4/Letter-sized Wifi QR
code sheets.
It takes URL parameters:
* eventName: this is either the name of an event or a URL to a logo for it
* ssid: network SSID
* psk: network password; if not set, the network is assumed to have no password
* hidden: if present, the network is assumed to be hidden
