docs: creating storefront

[field123]

Describe your changes

• running storefront locally
• using application keys
• env variables concept placeholder
• simple troubleshooting section
• updated introduction
• storefront deployment with vercel

Issue ticket number and link

n/a

Checklist before requesting a review

• I have performed a self-review of my code
• If it is a core feature, I have added thorough tests.
• I've added a Changeset for my changes - Click here to learn what changesets are, and how to add one

[changeset-bot]

⚠️ No Changeset found

Latest commit: 47ae85d

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[netlify]

✅ Deploy Preview for next-algolia-ep-cli ready!

Name	Link
🔨 Latest commit	47ae85d
🔍 Latest deploy log	https://app.netlify.com/sites/next-algolia-ep-cli/deploys/65aea00ab45e5f00085511bd
😎 Deploy Preview	https://deploy-preview-157--next-algolia-ep-cli.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated (UTC)
composable-frontend-algolia	❌ Failed (Inspect)			Jan 22, 2024 5:04pm
composable-frontend-docs	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Jan 22, 2024 5:04pm
composable-frontend-simple	❌ Failed (Inspect)			Jan 22, 2024 5:04pm