Mailer-16: feat: add secrets invoke from aws secrets

[maskeynihal]

This pull request primarily focuses on a shift in the way the application handles secrets, moving from a simple environment variable-based approach to utilizing AWS Secret Manager. The changes involve modifications to the configuration files, the introduction of new strategies for secret management, and adjustments to the mail service to accommodate these changes.

Key changes include:

Secret Management:

• src/strategies/secretStrategies/awsSecretStrategy.ts: Implemented AWS Secret Manager to fetch secrets. This involves creating a new SecretsManager client and retrieving the secrets from AWS.
• src/strategies/secretStrategies/envSecretStrategy.ts: Created a new strategy for fetching secrets from environment variables.
• src/strategies/secretStrategies/secretStrategy.ts: Created a new strategy to get secrets either from AWS Secret Manager or environment variables.

Configuration Changes:

• package.json: Added the AWS SDK for JavaScript as a dependency to interact with AWS Secret Manager.
• src/config/aws.config.ts: Created a new configuration file for AWS settings, including the region and Secret Manager name.
• src/config/mail.config.ts: Refactored the mail configuration to fetch mail settings from the new secret management strategies.
• src/providers/awsConfigStorage.provider.ts: Created a new provider for storing AWS configuration settings.

Mail Service Adjustments:

• src/services/mail.ts: Refactored the mail service to use the new mail configuration and made the send method asynchronous to accommodate the asynchronous nature of fetching secrets. [1] [2] [3]
• src/services/mailServer.ts: Adjusted the sendMail method to use the new mail configuration. [1] [2]

[maskeynihal]

resolves #16

[maskeynihal]

closes #2