Terraform Registry Support: Add support for token configuration that terraform supports.

[yorinasub17]

The initial version of Terraform Registry support introduced an environment variable for providing API tokens to terragrunt, but this is not how terraform authenticates. We should update the feature to support parsing the terraform authentication configuration.

Note the following caveat from the original PR:

Ideally we would be able to reuse code from Terraform. However, terraform has moved to packaging all its libraries under internal so that you can't use them as a library outside of Terraform. To respect the direction and spirit of the Terraform team, I opted for not doing anything funky to workaround the limitation (like copying those files in here).

[begemotik]

Would be nice to get it implemented.

[k2m30]

Gentlemen, any updates?

[pasinski]

Upvoting it too.

[luis-guimaraes-exoawk]

Any news?

[shaheerkhan12605]

Any updates ?

[yhakbar]

Hey folks!

Your feedback has been heard, and we're going to actively look into what we can do to support this.

[maciob]

Hey, any updates on this feature? It's really highly requested by community.

[VincentLim]

Any update ? It's blocking if you have to work with multiple private registries