Checkpointing to original mesh

[jorgensd]

A persistent checkpoint that writes function data as it would be on the input mesh.

One can either use write_mesh_input_order to write a mesh to a checkpoint file in the same order as the "input"-mesh or simply reload the mesh from file.

A function should be written with: write_function_on_input_mesh
and read with read_function (no API change for reading).

Other fixes

• Fixes to compute_index_owner for corner case
• Use Ruff for formatting
• Fix numpy casting warnings in test

[jorgensd]

@marchirschvogel @francesco-ballarin: Ready for review