Multiple minor fix and optimization

Multiple minor fix and optimization
Fix LittleFS filename size.

Minor fix and add support for SYST command

In this release, we are applying several fixes and integrating the SYST command (thanks @MartinMueller2003)

Fix ESP32 rename on SD

Fix ESP32 rename on SD (thanks @scuba-hacker) #44

Fix esp8266 Ethernet (w5x00) issue and explain solution for ESP32 Ethernet (w5x00), add new Networks management

Fix esp8266 Ethernet (w5x00) issue and explain solution for ESP32 Ethernet (w5x00), add new Networks management

Fix SPIFM external SPI Flash date management (add SPIFM esp32 example)

Fix SPIFM external SPI Flash date management (add SPIFM esp32 example)

Add support for Raspberry Pi Pico W and rp2040 boards, Fix SD card config

Add support for Raspberry Pi Pico W and rp2040 boards, and fix SD card config

Soft AP IP management, more disconnect event

Soft AP IP management, more disconnect event and SD_MCC

Fix path on SD card variant

Fix path on SD card variant and minor fix

Minor fix

Minor fix (removed Serial.printf).

Add UTF8 support and basic management of file length.

To support special characters and various languages I add UTF8 support, (thanks to @pabler).
And add minimal check of file length.