Feature request: Add wifi slots to remember multiple AP's

[mozzwald]

Feature request from https://atariage.com/forums/topic/332459-fujinet-without-the-net/?do=findComment&comment=5043503

what about having FujiNet remember maybe up to 10 previous WiFi portals and associated passwords, so that if it sees one of these when doing the power-up search it can automatically log-in. This would make it work just like your phone or tablet, and save the headache of having to re-enter this information every time you switch location.

The esp32 only stores the last known network so this would require adding "slots" for wifi networks and corresponding passphrases. These would be saved in the INI file and if the default network is not available, call that list and iterate through them.