Add GitHub Actions workflow and Makefile for test automation

We should add a GitHub Actions workflow and a Makefile to automate running tests for individual Pulumi samples. These should be modeled after the existing workflows and Makefiles used in:

• localstack-samples/localstack-pro-samples/Makefile
• localstack-samples/localstack-pro-samples/.github/workflows/makefile.yml

Requirements:

• Create a top-level Makefile to run install, lint, start, stop, and test commands for each Pulumi sample directory (similar to pro-samples).
• Add a GitHub Actions workflow under .github/workflows/ to run CI tests for all samples, similar to the referenced pro-samples workflow.
• Ensure the workflow installs dependencies, sets up LocalStack, pulls the Docker image, and executes tests using the Makefile.
• Link to relevant references for implementation:
  • Makefile from pro-samples
  • Workflow from pro-samples

This will keep testing consistent across all LocalStack sample repositories and simplify maintenance.