feat: add Vercel KV

[prplecake]

Would fix #2516

Note: Unstorage's Vercel KV driver is currently in beta.

This appears to be working for my Vercel deployment (https://elk.compostintraining.club). I can verify there is data in Vercel's KV storage.

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[Kitanit]

can you help me how to correctly write each parameter in ENV and what should I put in the key value?

[prplecake]

@Kitanit

Setting the following environment variables was enough to get it working for me:

NUXT_STORAGE_DRIVER=vercel
KV_REST_API_URL=
KV_REST_API_TOKEN=

Where the URL and Token would be given to you by Vercel. env and base are optional according to the docs linked below.

More info on the kv driver: https://unstorage.unjs.io/drivers/vercel