Add deployment docs for Layer0

[adebiyi-al]

NOTE: All development is currently focused on Sapper's successor, SvelteKit: https://kit.svelte.dev/ We are not adding new features to Sapper. While we might fix some particularly pressing or easy to address bugs, it's highly unlikely that most PRs will be reviewed.

Before submitting the PR, please make sure you do the following

• [ ] It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs
• [ ] This message body should clearly illustrate what problems it solves.
• [ ] Ideally, include a test that fails without this PR but passes with it.

Tests

• [ ] Run the tests with npm test and lint the project with npm run lint

[benmccann]

It would be better to create a SvelteKit guide. Sapper is a legacy framework that has been succeeded by SvelteKit

[adebiyi-al]

Great, @benmccann Thanks for the heads-up.