Apply ESP32 Client.h Arduino API breaking fix issue #370

Fix issue #367 for compilation error in ESP32 Core v3.1.x

Fix Raspberry Pi Pico compilation error

Fix SMTP message sending result issue #349

Fix SMTP message address-list issue #348.

Set default BearSSL Rx buffer for IMAP to 2k to prevent ESP8266 OOM

Fix IMAP RFC822 'From' header parsing issue.

Update for internal client.

Add support non-ascii characters (UTF-8) in SMTP message.

Fix filesystems, native Ethernet and Ethernet integration issues.