driver: wifi: esp32: add APSTA support

The ESP32 Wi-Fi driver previously did not support APSTA mode,
enabling AP mode would disable STA mode and vice versa.
Support for APSTA has been added by introducing additional
network interface: one for STA (Interface 2) and one for
AP (Interface 1). The CONFIG_ESP32_WIFI_AP_STA_MODE option in
Kconfig now allows enabling or disabling this support.

Signed-off-by: Muhammad Haziq <muhammad.haziq@zintechnologies.com>