[KV] Adding tutorial for accessing assets

[Oxyjun]

Summary

This PR is a continuation of https://github.com/cloudflare/cloudflare-docs/pull/15495.

Syntax has been brought in-line to meet docs standards in astro.

Screenshots (optional)

Documentation checklist

• [ x] The documentation style guide has been adhered to.
• [ ] If a larger change - such as adding a new page- an issue has been opened in relation to any incorrect or out of date information that this PR fixes.
• [ ] Files which have changed name or location have been allocated redirects.

[Oxyjun]

One question - we refer to the "Cloudflare Portal" in one section. Do we mean "Cloudflare Dashboard"?

[cloudflare-workers-and-pages[bot]]

Deploying cloudflare-docs with    Cloudflare Pages

Latest commit:	4b4c690
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Preview URL:	https://8377a9fc.cloudflare-docs-7ou.pages.dev
Branch Preview URL:	https://jun-kv-response-assets-tutor.cloudflare-docs-7ou.pages.dev

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[github-actions[bot]]

Files with changes (up to 15)

Original Link	Updated Link
https://developers.cloudflare.com/kv/examples/workers-kv-to-serve-assets/	https://jun-kv-response-assets-tutor.cloudflare-docs-7ou.pages.dev/kv/examples/workers-kv-to-serve-assets/
https://developers.cloudflare.com/kv/examples/	https://jun-kv-response-assets-tutor.cloudflare-docs-7ou.pages.dev/kv/examples/

[thomasgauvin]

This needs to land in it's own Examples section/have a sidebar item since it is first party content. Tutorials page seems to be a list of external links so content gets lost here. I've opened this PR to merge these changes into this one https://github.com/cloudflare/cloudflare-docs/pull/16433