Moving the mesh information to the (U)XGrid class

[erikvansebille]

This PR cleans up the different ways in which mesh type information ("spherical" or "flat") was used in v4. It is now a property of the (U)XGrid class

• Chose the correct base branch (main for v3 changes, v4-dev for v4 changes)
• Fixes Clean up the mesh_type property of the Grid #2154
• Added tests

[VeckoTheGecko]

Agreed that this does clean things up significantly.

Do we want to rename mesh to mesh_type? In v3 we used mesh, in v4-dev we were inconsistent (mesh and mesh_type). I agree we should just chose one, but I don't personally find mesh to be confusing naming (especially since we have type annotations), and the renaming of the public variable seems more confusing for users than keeping the original. This is a nitpick - if you feel strongly about mesh_type go for it.

[erikvansebille]

Agreed that this does clean things up significantly.

Do we want to rename mesh to mesh_type? In v3 we used mesh, in v4-dev we were inconsistent (mesh and mesh_type). I agree we should just chose one, but I don't personally find mesh to be confusing naming (especially since we have type annotations), and the renaming of the public variable seems more confusing for users than keeping the original. This is a nitpick - if you feel strongly about mesh_type go for it.

I see your point about trying to keep the API as similar as possible. Let's indeed then go for mesh. I'll update the code