Build Kiso Core as a library

[elbosch]

In order to simplify the build process we shall make the build process more independant from building everything with the Kiso build system.

• [ ] build Kiso in Folder core as libKiso (for a particular MCU and OS)
• [ ] build BSP as LibBsp (for a particular Board and MCU)
• [ ] build 3rd PartyLibraries
• [ ] build application and link with BSP, LibKiso and 3rd party.

So we can guarantee that Kiso can be better used inside other platforms e.g. XDK Workbench.

Note: In the future we shall also think about to separate the LibKiso into different parts: LibKisoCore, LibKisoDrivers (LibKisoConnectivity, LibKisoSensors, LibKisoStorage, ...)

[HansUweRempler]

Roadmap from steering committee #1 decision: XDK higher prio than ethernet (STM32F7)