[website] Fix ghcn website example

[felixpalmer]

For #8193

Background

Change List

• Convert example to Typescript
• Use MeshAttributes for borderMesh
• Fix wireframe rendering in SimpleMeshLayer

[ibgreen]

Nit: What on earth is ghcn? Do we have to have such a cryptic name? We are pretty strict with asking people to type out variable names - should we not apply at least a minimal similar standard for directories?

[felixpalmer]

@ibgreen it refers to the dataset, Global Historical Climatology Network. I'd be in favour of renaming examples/website/ghcn > examples/website/orthographic-view as it more useful to see what the example demonstrates rather than what it contains

[ibgreen]

I would vote for that. Should probably be separate PR, or open a ticket.

If breaking example perma-links are a concern, it is fairly easy to add redirects in docusaurus. https://github.com/visgl/math.gl/blob/master/website/docusaurus.config.js#L107