[FEATURE] Dependencies as submodules

[psiha]

Switch to using dependencies (such as kumi) as submodules (or packages or...) instead of as 'flattened detail headers'.
(makes collaboration easier)

[jfalcou]

is CPM + cmake level option to control yes/no on dependencies ok for your use case ?

[jfalcou]

TTS and other sub-level dependencies are being rewritten at the infrastructure level to garantee usage like this.
We'll end up using CPM to drag them as it is working properly with normal FIndPackage level + we'll adda -DKWK_EXTERNAL_DEPENDENCIES option to skip it entirely

[jfalcou]

eve, tts, kumi and raberu are now fetchable via CPM.
SO next step is to amend Kwiaku to use CPM to fetch them.