Remove inspect_meshes_folder?

[adamltyson]

There's a function brainglobe_atlasapi.atlas_generation.mesh_utils.inspect_meshes_folder that we used to use to inspect meshes. I don't think we use this anymore, and we have many other documented ways to visualise meshes.

I propose we remove this (and it's reference in the docs) and focus on napari-based ways to inspect the meshes?