USF-2163: Further development of Storefront Builder content

[bdenham]

Purpose of this pull request

This pull request (PR) provides the foundation content and how-tos for using the Storefront Builder to develop content for a storefront site.

What is included?

Content repository
Document Authoring (DA)
In-content Authoring (WYSIWYG) - in development. Included with Adobe Commerce as a Cloud Service.
GenAI content variations

How do I get started with Storefront Builder now?

If you already have storefront project with Sharepoint/Google Drive
If you just start with storefront following the tutorial

Associated JIRA ticket

https://jira.corp.adobe.com/browse/USF-2163

Staging preview

https://commerce-docs.github.io/microsite-commerce-storefront/merchants/storefront-builder/

Affected pages

https://experienceleague.adobe.com/developer/commerce/storefront/merchants/storefront-builder/ and subtopics.

[gitguardian]

️✅ There are no secrets present in this pull request anymore.

If these secrets were true positive and are still valid, we highly recommend you to revoke them.
While these secrets were previously flagged, we no longer have a reference to the
specific commits where they were detected. Once a secret has been leaked into a git
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Find here more information about risks.

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[bdenham]

This PR represents the baseline documentation for Storefront Builder, to be expanded on with more content and specific tutorials when I come back from PTO.

[fnhipster]

Approved with suggestions.