adding features

[tharun634]

• Add a CLI for the generated python and js libraries
• refer : https://www.npmjs.com/package/dotenv-flow
• refer: https://itnext.io/how-to-create-your-own-typescript-cli-with-node-js-1faf7095ef89
• should take in stage and command to run as input, and select the corresponding .env.stage file.
• Add jsii support for different key managers, start with AWS can be referred in the .env file as ssm:/path/to/service/id
• refer : https://www.serverless.com/framework/docs/providers/aws/guide/variables
• refer : https://github.com/rochacbruno/dynaconf/issues/586