Access point: Create SSID dropdown instead of manual entry

[tcsullivan]

1. Create the access point in case the WiFi is not found after some amount of time.
2. Change SSID form field to a dropdown that's populated from a network scan? Would need to scan before entering AP mode I think...

[tcsullivan]

Added WiFi connection timeout on the onboarding-prep branch.

[tcsullivan]

More than one user has had issues with trying to connect to 5GHz WiFi networks; the ESP32 we're using unfortunately doesn't support these. If we can implement this dropdown, then that should ensure that users can only connect to compatible networks.