AAI-204 Deploy backend service to AWS via GitHub Actions

[marius-mather]

Description

AAI-204: Use AWS CDK to deploy the service to AWS on each commit to main.

Changes

• CDK deployment stack
• GitHub Action to run the deployment on each commit to main, or manually. Should run after the latest changes are built and uploaded to the AWS container registry

Checklist

• I have commented my code, particularly in hard-to-understand areas
• I have added unit / integration tests that prove my fix is effective or that my feature works
• I have run all tests locally and they pass
• I have updated the documentation (if applicable)

[amandazhuyilan]

Some nitty suggestions - overall looks great!

[marius-mather]

Thanks, @amandazhuyilan , have made those suggested changes now