* 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
