1.0.3 make location optional

make location optional (#14)

This PR adds support for configurations without locations, allowing the
envars tool to work in scenarios where location-based scoping is not
needed.

- Made the --loc parameter optional in the init command
- Updated location validation logic to handle cases where no locations
are configured
- Added conditional rendering of the locations field in YAML output

in AWS we have prod, staging in Master and Sandbox
but in GCP data-platform we only have prod, staging