Grids tutorial MVP compliance

[undavide]

Description

From the tutorial's changelog:

• apiProxy() now accepts "documentSandbox" as a parameter, instead of "script".
• manifest.json now accepts "documentSandbox" in lieu of the "script" property for the document sandbox entry point. This requires the "@adobe/ccweb-add-on-scripts" dependency to be updated to version "^1.1.0" or newer in the package.json file.
• addOnSandboxSdk is now imported from "add-on-sdk-document-sandbox" (it used to be "AddOnScriptSdk").
• editor and other modules are now imported from "express-document-sdk" (it used to be "express").
• The webpack.config.js file has been updated to reflect the new imports (see the externals object) in both the express-grids-addon and express-addon-document-api-template projects.
• Constants are now constants (lowercase), and their enums have changed (e.g., BlendModeValue is now BlendMode).
• translateX and translateY have conflated in the new translation property.
• The group's warning about the operations order (create, append, fill) has been removed; groups can now be created, filled and appended.

⚠️ Color POJO changes are pending, waiting for HZ-32556 to be merged.

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[hollyschinsky]

LGTM