Add support for env vars and Pseudo TTY in hooks

[bdwyertech]

Description

Add support for env vars and Pseudo TTY in hooks. TTY allows me to have colorized output from hook output for a tool such as helm-diff.

TODOs

Read the Gruntwork contribution guidelines.

• Update the docs.
• Run the relevant tests successfully, including pre-commit checks.
• Ensure any 3rd party code adheres with our license policy or delete this line if its not applicable.
• Include release notes. If this PR is backward incompatible, include a migration guide.

Release Notes (draft)

Added / Removed / Updated [X].

Migration Guide

[denis256]

Hi,
will be helpful to add documentation on how to use the new flag and to have tests that will track that flag is still working

References:
https://github.com/gruntwork-io/terragrunt/blob/master/docs/_docs/02_features/hooks.md
https://github.com/gruntwork-io/terragrunt/blob/master/test/integration_test.go