Refactor "Intended" Functionality in README

[philipc2]

We mention "intended" functionality in our README. This should be updated to outline our "Supported" functionality.

Below is the section I am referring to.

UXarray Functionality

The following intended functionality has been inspired by discussions with members of the scientific community, within the SEATS Project and Project Raijin, and on several community platforms such as Xarray GitHub Repository. The UXarray team is receptive to additional functionality requests.

Intended Functionality for Grids

• Support for reading and writing UGRID, SCRIP ESMF, and Exodus formatted grids.
• Support for reading and writing shapefiles.
• Support for arbitrary structured and unstructured grids on the sphere, including latitude-longitude grids, grids with only partial coverage of the sphere, and grids with concave faces.
• Support for finite volume and finite element outputs.
• Support for edges that are either great circle arcs or lines of constant latitude.
• Calculation of face areas, centroids, and bounding latitude-longitude boxes.
• Triangular decompositions.
• Calculation of supermeshes (consisting of grid lines from two input grids).

Intended Functionality for DataArrays on Grids

• Regridding of data between unstructured grids.
• Global and regional integration of fields, including zonal averages.
• Application of calculus operations, including divergence, curl, Laplacian and gradient.
• Snapshots and composites following particular features.