GraphQL: Add documentation for storeConfig queries in 2.3.1

[keharper]

Community engineering issue

Type of Doc:

• New topic
• Topic Update, Devdoc link:
• Other

Magento 2 GitHub Issue:
magento/graphql-ce#128

Magento 2 GitHub PR: magento/graphql-ce#182

Magento 2 version:

• 2.1.X
• 2.2.X
• 2.3.1
• back port
• forward port

Notifications of Changes:

• Changes to Admin interface?
• New software requirements?
• New REST endpoints or updated GraphQL query syntax?
• New command line option?

Content

GraphQL PR-182 adds the StoreConfig type to the ThemeGraphQl and CmsGraphQl modules. The documentation for the storeConfig queries will need to be updated, but I don't know its source module right now.

[keharper]

The ThemeGraphQl module also needs to be documented.