This updates the minimal supported version of CMake to 3.16, which in turn enables us to use more CMake features and have a cleaner build system.
This is the version that provides most new features and also the one we use in our latest docker image for CI.
This commit updates the handles for the timer, task and event_group
modules to struct type. This matches upstream freertos source.
Signed-off-by: Sudeep Mohanty <sudeep.mohanty@espressif.com>