Wi-Fi QR: special characters in the network name and password now scan correctly

The Wi-Fi QR standard requires ; , : " and \ in the network name and password to be escaped. They were written as-is, so a password containing ;, for example, did not follow the standard and could be read wrongly.

The generator and the edit page now escape these characters according to the standard, and the card on the scan page shows and copies the value correctly.