Review XArray implementation in easyCore

[rozyczko]

First step in the TOF plan

[rozyczko]

Looked at develop 65ce490

easyCore\Datasets\xarray.py

two main classes:

• easyCoreDatasetAccessor

• easyCoreDataarrayAccessor

  • core_object seems to be redundant. is it just a holder for metadata? if so, why use weakref?

  • add/remove_coordinate/variable - switching to scipp will make this redundant, since scipp has units and errors built in

  • why removing weights in fitting? (l. 423) in dataset but retain them for dataarray? (l.692)