ADR Suggestion: DescriptorArray

[henrikjacobsenfys]

For EasyCrystallography and EasyDiffraction, we need to have Descriptors that are arrays. We agreed that it should be named DescriptorArray.

It will inherit from DescriptorBase, and will be implemented as scipp variables using scipp.array.

It will have all the same methods as DescriptorNumbers, including element wise+,-abs, neg.

We will follow numpy conventions. This means that * and / can only be done with Numbers or DescriptorNumbers, and will be element wise.

Matrix multiplication and division will be implemented as well, using Numpy. We will follow the Numpy naming scheme. Numpy Arrays and DescriptorArrays will be accepted inputs.

[rozyczko]

I think this is all correct but should be converted to a task in the EasyScience project https://github.com/orgs/EasyScience/projects/21
We have all agreed that this should be done and the new class should have the same behaviour as the other derived classes for different types.

New features, especially extensions of existing functionality are best described on the project board as they are then easy to manage in the workflow TODO -> IN PROGRESS -> DONE

[henrikjacobsenfys]

We will also allow addition etc. with DescriptorNumbers