Add storybook to Svelte TS project

[gcsecsey]

Pull Request Template

Description

This PR adds Storybook with Typescript support to the agnostic-svelte-ts project:

• Stories can now use the Svelte native format
• The copystyles.cjs file and the npm script invoking it is copied over to the project, but currently throws an error because of missing components
• Prettier config is updated to use the SvelteKit defaults as well as settings from agnostc-svelte
• The Alert component is copied with some type errors fixed and the new story format

Related to #127

Testing steps

cd agnostic-svelte-ts
npm i && npm run storybook

Storybook should build all stories with TS sources and common CSS successfully:

Checklist:

Please delete options that are not relevant.

• [X] Is this a new feature
• [X] Have you submitted new feature or bugfix issue? Unless it's a small bugix, we generally prefer to track PRs against an issue which starts a dialogue to give us context.

We realize above checklist is pretty intimidating, reach out with an at mention on your issue if you're interested in contributing but need some clarifications!

[roblevintennis]

Notes

• Was able to comment out everything but the Alert from agnostic-svelte-ts/copystyles.cjs and successfully run npm run syncStyles and it copies over said styles into <style>...</style>
• Ran npm i and then npm run storybook:

I think this all checks out. Thanks @gcsecsey -- I'm going to merge it 🙏 ❤️ 🚀