EREGS-2858: Convert Static-Assets serverless to CDK

[addis-samtek]

Convert Static Assets Stack from Serverless to CDK

Resolves EREGCSC-2858

Description

This PR migrates the Static Assets infrastructure from Serverless Framework to AWS CDK. This is part of our broader initiative to standardize our infrastructure as code using CDK.

This pull request changes:

• Introduces new StaticAssetsStack CDK construct
• Migrates CloudFront distribution configuration to CDK
• Converts S3 bucket configuration for static assets
• Implements WAF rules using CDK constructs
• Adds Python Lambda layer for dependencies
• Configures proper resource naming using StageConfig
• Implements cross-stack resource sharing (exports/imports)

Verify Deployment

Create MR, verify deployment in ephemeral environment through GitHub Actions pipeline (check CloudFront distribution, S3 bucket and cache invalidation in AWS Console after pipeline completes).

[github-actions]

✨ See the Django Site in action ✨

[cgodwin1]

Approved tentatively noting that before prod-ready, needs Django's collectstatic in the action, and also will need the step to build and deploy Vue assets post-Django-deploy.

Additionally, some cleanup will be needed during the refactor stage: namely removal of debug statements and general linting.