Added WIP files before decided to abandon this project

[antonbabenko]

I have decided to not continue active development of this project because it has become possible to achieve the same using Terragrunt natively since v0.19.20, which was released 15th of August 2019.

Read Passing outputs between modules for more details.

Consider checking antonbabenko/terragrunt-reference-architecture repository for real code where Terragrunt is used.

I will focus my time as open-source developer on terraform-aws-modules and modules.tf.

PS: I think there is still need in functionality provided by this project for pure Terraform projects.