Make environment management independent of AWS

[betabandido]

At this moment TerraformDevKit requires users to provide AWS credentials. In addition to that, it is not clear how easy or transparent is to use other providers (e.g., Azure or Google). For instance, prod and test environments require manual input of the AWS profile.

Perhaps users should just pass all credentials info as part of the extra vars that end up being used when rendering the templates. For safety reasons, instead of asking for the profile name, we could just use some sort of captcha (e.g., asking for the result of a mathematical operation as well as printing some clear warning message).