Domain configuration

1. Edit domain.yml and provide the domain name and the cert's Arn.
2. Run npx sls deploy to create the custom domain config on API Gateway (this doesn't create a DNS record)

Service deployment

1. To deploy a service, run npx sls deploy in its subdirectory
2. Services are available at the /a and /b base paths configured in their serverless.yml (e.g.: https://api.example.org/a/hello)