By doing so, the application will be able to define its own esp_app_desc generated at their discretion, with help of whatever build process they use, and removes the necessity to rebuild esp-idf every time only to have the esp_app_desc updated.
Removes the patch necessary for https://github.com/esp-rs/esp-idf-sys/pull/136, where we are building esp-idf and basically linking it as a static library. The process building the library doesn't have access to the real application version or the build time, since we are only rebuilding esp-idf if the sdkconfig changes.
