add converter NDArray to primitive arrays

[devcrocod]

There is a converter to a flat array, you need to add a converter to nested arrays:

MultiArray<Float, D?>.toFloatArrayD?(): Array<...<FloatArray>>

Similar to toListD2, toListD3, toListD4

[therealansh]

hey @devcrocod i can try this one. Are we planning to add all the primitive array with all the dimensions like D1, D2 and so on for every primitive array?

[devcrocod]

@zaleslaw
Look here, please. That's what you need?

[zaleslaw]

Looks like what I need in KotlinDL