Add support for story-level tags

[JReinhold]

Fixes #203

This PR adds support for story-level tags as described at https://storybook.js.org/docs/writing-stories/tags

Ie. <Story name="..." tags={['!dev', 'autodocs']} />

• Extracted tags from Story attributes
• Forwarded extracted stories to the index inputs
• Updated StoryProps types to support the tags prop
• Added test stories that demonstrates/tests the feature
• Upgraded the internal Storybook to ~8.1.0, because that's the first version that reliably works with tags as we know it today.

If you want to use this feature today, make sure you're at least on Storybook version 8.1.0

📦 Published PR as canary version: 4.1.7--canary.207.1873b6d.1

✨ Test out this PR locally via:

npm install @storybook/addon-svelte-csf@4.1.7--canary.207.1873b6d.1
# or 
yarn add @storybook/addon-svelte-csf@4.1.7--canary.207.1873b6d.1

[xeho91]

This isn't following CSF v3.0 format, right? Asking to clarify if we're supposed to preserve this behavior in v5 of this addon (on the next branch).

[JReinhold]

That's a good question. I think our legacy support should support this, but the new API shouldn't, as this is not like regular CSF, and I only added it here because it's how Meta already works.

[shilman]

🚀 PR was released in v4.1.7 🚀