Describe the code sample using zephyr:code-sample directive to help
with making it easier to find from API reference.
Also cross-referenced main bindesc page from the sample.
Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>
Improved the README.md of the hello_bindesc sample by adding a
note about non existing bin files and referencing the relevant
parts of the documentation.
Signed-off-by: Yonatan Schachter <yonatan.schachter@gmail.com>
