This PR Updates the NDArray => Tensor.
Both tensor and ndarray are commonly used terms.
Because the term Tensor is getting more common in the context of ML,
we do the rename to stay more aligned with torch.Tensor and DLTensor.
* [Runtime] Allow offset to be specified in NDArray::CreateView
Prior to this commit, the `NDArray::CreateView` method could produce
an aliasing view of an existing array with a different shape or
datatype, but the view was required to have the same
`DLTensor::byte_offset` as the existing array. This commit updates
the `NDArray::CreateView` method with an additional parameter,
specifying the offset of the view relative to the existing array.
* Change type of `relative_byte_offset` from `size_t` to `uint64_t`
Both to match the type used in `DLTensor::byte_offset`, and to resolve
compilation errors on 32-bit platforms, which fail to compile due to a
missing `Type2Str` specialization.
Tianqi Chen