Group merchant services schema together

[keharper]

Purpose of this pull request

This PR adds a new overview page for Adobe Merchant Services GraphQL and reorganizes the left navigation to group Catalog Service, Live Search, and Product Recommendations under a unified "Merchant Services Schema" section.

Staging build: https://developer-stage.adobe.com/commerce/webapi/graphql/schema/storefront-services/

Jira: COMDOX-1508

Affected pages

• New page: https://developer-stage.adobe.com/commerce/webapi/graphql/schema/storefront-services/
• Navigation restructuring affects all pages previously listed under separate Catalog Service, Live Search, and Product Recommendations nav sections

What's New highlights

whatsnew
Added Adobe Storefront Services GraphQL Schema — an overview page explaining how Catalog Service, Live Search, and Product Recommendations GraphQL schemas relate to each other, how they differ from the core Commerce GraphQL schema and from Adobe Commerce Optimizer, and guidance on when to use each.

[meker12]

Over all looks pretty good. Have some comments about clarifying the different contexts.

[meker12]

Over all looks pretty good. Have some comments about clarifying the different contexts for using extensions on Adobe Commerce on cloud or on-premises vs Adobe Commerce as a Cloud Service.

Also, need to make it very clear that Adobe Commerce as a Cloud Service supports only the Storefront Services extensions. Support for using ACCS with ACO Merchandising services is not yet available.

[meker12]

Some additional updates required. Complete search and replace for "Merchant Services " > "Storefront Services"

I think we should ask someone to do a technical review of this content. Someone that knows both services -- Ask in Commerce catalog service documentation channel, and in the Commerce Optimizer Planning Slack channels

I did approve to prevent blocking the merge.

[meker12]

@keharper Can you add the JIRA ticket associated with this work. Then, this PR can be merged.