Bugfix/PPPOS fix stack smashing, modify get operator and add access technology
Closes IDFGH-2262 and IDFGH-3844
See merge request espressif/esp-idf!11557
(cherry picked from commit 5d92cdc5d9)
d59ffd91 Expose get operator name command. Add get access tech
935edc9e rename dce parameter
7f3bcc13 esp-modem: prefix the crash issue both bg96 and sim800l in OVERALL mode
The MQTT broker URL used as default in the examples has ceased operation. All examples and documention have been updated to point to the new domain mqtt.eclipse.org.
This also required an update of the python example test scripts to use TLS 1.2
1. add support for ESP32 DTE
2. add support for SIM800/BG96 DCE
3. add PPPoS setup procedure
4. add support for SMS
5. add mqtt example after PPP connection established
