[BUG] Single Stack Deployments vs. Multi Stack Deployments

[cremich]

Describe the issue

Based on community feedback, single-stack deployments are a common pattern. The current version of project rules suggest a multi-stack approach.

Additional context

• https://www.ranthebuilder.cloud/post/aws-cdk-best-practices-from-the-trenches
• To be added.

Possible solution

Add required rules to cdk-project-structure.md and cdk-design-patterns.md to enforce a single-stack approach