CMake support for modules-enabled kernel

[Jasinsky]

CMake is lacking support of modules enabled kernel. Popular CMake use case is to fetch external dependencies with FetchContent.

Desired behavior would be introduction of CMake flag (cache variable) that selects kernel flavour.

Alternative is manual patching of CMake within build systems consuming external dependencies (which I am doing now)

If community gives positive feedback I can provide PR which enables given support.

[fdesbiens]

This makes sense to me, @Jasinsky.

@eclipse-threadx/iot-threadx-committers and @eclipse-threadx/iot-threadx-contributors: let's discuss this matter at our meeting next week.