refactor: update svelte -> vite in preparation for #3

[LeoDog896]

This PR aims to clean up the repository, to alleave any confusion from external developers, including:

• Dropping unnecessary dev-dependencies
• Simplifying dev scripts
• Moving to vite (sveltejs no longer uses only rollup for non-sveltekit projects)

This also closes #4, choosing to fully adopt Yarn for the project.

[LeoDog896]

I should mention that I heavily encourage the use of GitHub CD for the site instead of baking in the /public directory.

[Mitcheljager]

This has been superseded by f5d265e1c5d85708e778264e912739721292a71a