Proper rendering of credentials

[dangernil]

Feature description

As a user of the module we want proper render of credentials, without using vault provider

Why is it needed?

To make it easier to use the module.

Suggestion(s)/solution(s) [Optional]

Done in Presto module: https://github.com/fredrikhgrelland/terraform-nomad-presto/blob/master/conf/nomad/presto.hcl#L327

Definition of done

• Rendering credentials in .hcl file

Checklist (after created issue)

• Added label(s)
• Added to project
• Added to milestone

[zhenik]

@dangernil Wrong feature description -> As a user of the module we want proper render of credentials, without using vault provider

Take a look at #22