Integrate AWS Secrets Manager/Parameter Store for Zappa/Infrastructure deployments

[rudransh-shrivastava]

Is your feature request related to a problem? Please describe.

Eliminate steps 4 and 5 in Setting up the infrastructure by using AWS Secrets Manager/Parameter Store instead of environment variables.

This should also include the elimination of the use of environment variables in backend/zappa_settings.json.

Are you going to work on implementing this?

• Yes
• No

Additional context
Parent Issue: #2214

[rudransh-shrivastava]

Closing as completed in #2551