Move BLE sample apps from core to nimble repo about mynewt-nimble

[turon]

Cloning the sample apps for each platform isn't really scalable. The btshell app for example would require copying of a lot of code. Better would be to make the sample apps use NPL so they are portable across the various platforms.

[andrzej-kaczmarek]

apps like btshell are not really portable since they have dependencies on mynewt-core (e.g. console, shell) which are out of scope of NPL.

apps like bleprph or blecent (or we can add new apps) could be refactored in a way that it is easy to grab ble-related code and use in port for other OS easily. we may also add an ootb configuration to build on Linux in addition to Mynewt.

but in general I agree we can keep apps for NimBLE in mynewt-nimble instead of mynewt-core to make maintenance easier.

[sjanc]

note that sample application will be OS specific even if it will reside in nimble repo

[rymanluk]

Completed