[Ovmsdev] Support for Lilygo T-Call based module

[Info]

Hi,
I finished the implementation and documentation of the OVMS module based 
on the Lilygo T-Call A7670E board (ESP32 WROVER E and a Simcom A7670E).
The module is in operation since more than a month in my Smart EQ.

The hardware details can be found here: 
https://github.com/zbchristian/OVMS-Lilygo-based-Module

There are some limitations wrt the standard module:
- only 4MB Flash -> no OTA update
- no GPIO extender -> only 2 CAN buses
- no SD-card support

The required modification in the firmware:
- remapping of the ESP32 pins in ovms_peripherals
- replace some of the GPIO extender pins by standard ESP32 pins
- new hardware option in menuconfig (set CONFIG_OVMS_HW_BASE_LILYGO_1_0=y)
- Simcom 7670 modem support (already available in the OVMS repo)

All this is available in the branch lilygo-support of 
https://github.com/zbchristian/Open-Vehicle-Monitoring-System-3-Lilygo-Support

My question to the main developers: Is there interest to incorporate 
this into the official OVMS repository?

Best regards
    Christian