Commit f2c2393b30 (#2420) breaks lv_micropython esp32 port. Apparently main dependency is require for LVGL when building Micropython, otherwise GC related code breaks
This commit adds 'main' dependency to LVGL conditionally only if building inside lv_micropython.
* Removed src/lv_conf_zephyr.h
Removed src/lv_conf_zephyr.h as it is maintained in the Zephyr build it self.
* CMakeLists.txt: Added support for Zephyr RTOS
Added support to build LVGL as library for Zephyr RTOS
* Added support to use LVGL repo as Zephyr module
Added support to use the LVGL repository as a Zephyr module repository
* Removed LV_CONF_SKIP definition from CMake to avoid redefinition warnings; added more Kconfig options
* Bumped up version and removed unnecessary default values
* Added user data configuration to KConfig
* Moved user data options to "Feature Usage" menu
