Describe the problem

There's a desire to put docs for all the projects into the omnisite. vite-plugin-svelte doesn't really have a docs index page currently. There's the readme, but we might put different content on svelte.dev than what's there. There also isn't a clear order the docs pages should be displayed in the lefthand nav

Describe the proposed solution

Prefix the existing docs with 10-, 20-, etc. to provide an ordering that can be used in the lefthand nav. The docs with the smallest prefix should include some introductory material

Alternatives considered

it may be helpful to update the directory structure of various repos to align with each other, but I think that isn't strictly necessary and we can maintain a mapping of where docs live in each repo

Importance

i cannot use vite-plugin-svelte without it