v1.2.0 to enable scan of WiFi networks

### Major Release v1.2.0

1. Enable scan of WiFi networks for selection in Configuration Portal. Check [PR for v1.3.0 - Enable scan of WiFi networks #10](khoih-prog/WiFiManager_NINA_Lite#10). Now you can select optional **SCAN_WIFI_NETWORKS**, **MANUAL_SSID_INPUT_ALLOWED** to be able to manually input SSID, not only from a scanned SSID lists and **MAX_SSID_IN_LIST** (from 2-6 for ESP8266-AT or 2-15 for other)
2. Minor enhancement to not display garbage when data is invalid
3. Tested with new [Arduino Core for STM32 v2.0.0](https://github.com/stm32duino/Arduino_Core_STM32) and add support to new STM32L5 boards.
4. Enhance MultiWiFi connection logic
5. Enhance debugging feature