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.
Config options have been set such that BLE transport will be the default for ESP32
and SoftAP will be the default for ESP-S2.
CMakeLists.txt for all provisioning examples applicable for ESP32-S2 have also been updated
as these now work fine on ESP32-S2
Signed-off-by: Piyush Shah <piyush@espressif.com>