Clean up Archetype from SPA frontends (Angular & React) and SSR support

[UladzimirLitvinchuk1]

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 change cleans up the AEM Project Archetype by removing legacy frontend paths that are no longer aligned with the current product direction.

As part of the move toward Universal Editor, the archetype should focus on standard HTL-based site projects and stop carrying SPA-specific and SSR-specific scaffolding. In the same cleanup, the remaining headless Forms React artifacts were also removed so the archetype no longer ships React/Angular-based frontend variants.

This work was done in response to the official cleanup request for the archetype and is intended to reduce complexity, remove unsupported project options, and keep the generated project structure aligned with current best practices for AEM.

Main changes

Removed Angular and React SPA project support from the archetype
Removed SSR-related options, templates, configuration, and generated content
Removed headless Forms React/frontend artifacts and related archetype options
Simplified archetype metadata, post-generation cleanup logic, and module wiring
Updated template structure so generated projects now center on standard HTL components
Cleaned up related test fixtures and sample content that depended on SPA/SSR/headless frontend paths
Result
Generated projects are now simpler, HTL-first, and aligned with the Universal Editor direction instead of SPA/SSR-based site implementations.

Related Issue

Motivation and Context

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.