docs(terraform): Create atfvars.exampleFile for Required Variables

[carlagesa]

To make it easier for new developers to get started with the project, we should create a terraform.tfvars.example file. This file will list all the required variables with placeholder values and descriptive comments. This serves as clear documentation for what inputs are needed to run the project.

Acceptance Criteria:

• A terraform.tfvars.example file is created in the terraform/ directory.
• The file includes all variables defined in variables.tf without default values.
• Example values or comments are provided for each variable to explain its purpose.
• The .gitignore file is updated to ensure *.tfvars files are not committed, but terraform.tfvars.example is.