Request to add support for WPA Enterprise

[gagank1]

Is your feature request related to a problem? Please describe.
Currently the captive portal only supports WPA2. The ESP32 has WPA Enterprise support but it's not implemented by this library.

Describe the solution you'd like
An ideal solution would detect the type of encryption used by the access point and provide the necessary additional fields. An extra username field in the manual SSID form that defaults to WPA Enterprise when used would work in a pinch too.

Describe alternatives you've considered
I'm considering implementing the second one but it's more of a hack than a true solution. I don't have the web dev skills to implement the first.

Additional context
n/a