fix(CMake) split CMakeLists.txt, add options, includes and dependencies (#2753)

* fix(CMake) split CMakeLists.txt, add options, includes and dependencies

* fix(CMake) do not use 'project' keyword with ESP_PLATFORM

* fix(CMake) prefix includes with CMAKE_CURRENT_LIST_DIR

* Don't depend on CMAKE_CURRENT_SOURCE_DIR

* fix(CMake) rename baremetal.cmake to custom.cmake

* fix(CMake) add CMake documentation

cmake/zephyr.cmake

@@ -0,0 +1,14 @@
+if(CONFIG_LVGL)
+
+  zephyr_include_directories(${ZEPHYR_BASE}/lib/gui/lvgl)
+
+  target_include_directories(lvgl INTERFACE ${LVGL_ROOT_DIR})
+
+  zephyr_compile_definitions(LV_CONF_KCONFIG_EXTERNAL_INCLUDE=<autoconf.h>)
+
+  zephyr_library()
+
+  file(GLOB_RECURSE SOURCES ${LVGL_ROOT_DIR}/src/*.c)
+  zephyr_library_sources(${SOURCES})
+
+endif(CONFIG_LVGL)