Use sdkconfig.defaults to define minimal set of default config

[fadushin]

This change allows the build system to create Kconfiguration that is appropriate for the IDF-SDK platform, while also allowing users to make changes to the sdkconfig file without accidentally checking those changes into version control.

Signed-off-by: Fred Dushin [email protected]

These changes are made under both the "Apache 2.0" and the "GNU Lesser General Public License 2.1 or later" license terms (dual license).

SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later