Stripe Link File Delivery 1.2.0

Massive performance improvements:

1. Added Memory recommendation, ensuring 1 full vCPU provisioning
2. Removed aws-sdk dependency and replaced it with aws-sdk-js-v3 modules for signinf and s3, idea credit Mykhailo Matviiv. 6MB total package, 1200ms cold, 400ms hot.
3. Changed the email sending method to a non-blocking call since the reply isn't used in any way other then logging, idea credit Mykhailo Matviiv and Lambda non-blocking tips from sensedeep. 6MB total package, 1200ms cold, 400ms hot.
4. Fully removed the import of AWS SDK, added type: module to package.json to rely on AWS Lambda's built-in shipped AWS SDK V3. 2.25MB total package, 1000ms cold, 350ms hot.
5. Added webpack build step to further reduce the package size, tree-shake it and minmize. 78KB total package, 750ms cold, 200ms hot.
6. Replaced Axios with https and url, webpack with esbuild. 32KB total package, 720ms cold, 180ms hot.

Lambda Files 1.1.0

This release brings out more variables out to Environment or Stage, delivers a united Lambda but keeps the separate Lambdas in a subfolder. Updates the README.md for with better manual.
Added handling of session_id missing, improved the consistency of variable naming.

Lambda Files 1.0.0

This is the .zip files for Lambda functions generated as of commit 14925d5