cmake: introduce Deprecated module

The deprecated CMake module allows Zephyr to move deprecated code to a
centralized location from where it's both easy to get an overview of
deprecated code, and remove the code when it has been deprecated long
enough.

It further improve existing code, as the real CMake code now can be
changed from n-lines of deprecated code into a single line of the form:
find_package(Deprecated COMPONENTS <deprecated_name>)

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>