Centralize environmentd/orchestratord version defaults in Helm module

[bobbyiliev]

As @kay-kim suggested, currently we maintain default versions for environmentd/orchestratord in multiple places:

• terraform-helm-materialize
• terraform-aws-materialize
• terraform-azurerm-materialize
• terraform-google-materialize

Similar to how we're letting operator_version default to the Helm module's value, we could:

1. Define these version defaults only in terraform-helm-materialize
2. Remove the hardcoded defaults from the cloud provider modules
3. Let them inherit from the Helm module

This would reduce version synchronization overhead during releases.

Note: This change would be a nice companion to the automated version update workflow we're implementing #15

[bobbyiliev]

Fixed in #36