Terragrunt multi-module workflow

[nischalstha9]

Problem Statement

Currently, we are only able to run terragrunt plan and apply for purgable/ecs module. In case we want to update secrets via non-purgable/extras module, it's not possible.

Proposed Solution

Create a workflow that utilizes GitHub Actions environment for review based deployment. With this we can set option to run workflow with different input parameter. Currently, we will only allow extras and ecs module. But with necessary requirement, this can be updated easily.
This will make the workflow compatible for multiple modules as vpc, rds etc. too.