docs: Add a page with all the niceties typegpu provides

[aleksanderkatan]

• No need to worry about byte alignment,
• no need to worry about group and binding indices,
• buffer.asMutable(),
• await buffer.read(),
• (once we have them after feat: Add matrix transformation ops to std #1186 and such) extra std functions,
  and similar.

I think it would be beneficial in convincing potential users to have those listed all in one place, as bullet points with a short explanation or a link to other segment of the docs. I'd see it either on the Why TypeGPU? page, or on a new subpage.