* 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