SITES-14246 Clean up Archetype

[UladzimirLitvinchukAdobe]

Remove everything from Archetype for AEMCS & AEM 6.5 which is related to:

SPA frontends (Angular & React)
SSR support
Archetype should only support standard HTL components as everything else shall be handled by Universal Editor

Description

This pull request removes all legacy SPA-related functionality from the AEM Project Archetype, including Angular-based SPA modules, React-based SPA modules, SPA Editor integrations, and SSR support. The archetype is now aligned with the current Adobe strategy focused on Universal Editor.

What was done

• Removed SPA front-end modules (Angular / React)
• Removed SPA Editor integrations
• Removed SSR support (enableSSR)
• Removed SPA-specific clientlibs, templates, components, and POM dependencies
• Cleaned up documentation (README) to remove references to SPA front-ends
• Ensured archetype produces only standard HTL-based AEM projects

Related Issue

Motivation and Context

The Universal Editor provides a unified, framework-agnostic authoring experience and replaces the need for framework-specific SPA implementations. Maintaining Angular/React SPA scaffolding in the archetype is no longer required and introduces unnecessary complexity.
Removing this functionality ensures:

full alignment with Universal Editor adoption,

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

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.