Create module to validate all the environment variables and their types

[nelegatti]

The project needs a way to check if the required environment variables are set and with the correct value type. For example, if we intend to use AWS SES to send emails, verify if all env vars required for this logic to work are configured and valid, if not, prevent the application from starting.
The first idea is take advantage of class validator and create an implementation similar to this post , but we can implement choose different approach if it's a better option