Added following as part of this change
1. Removed auth_changed event
2. Updated doc regarding usage of WPA/WEP secuiry modes
3. Fixed WPA2 enterprise authmode threshold.
In wifi station example, set PMF(Protected Management Frames)
configuration to capable. Set WPA3 Feature in menuconfig enabled
by default. This will allow device to establish more secured
connection with AP's that support these protocols.
esp_netif_init() returns standard esp_err_t error code (unlike tcpip_adapter init), so shall be checked for the return value
Also to make the initialization code more consistent.
