replace deprecated template_dir for terraform

[hh]

We use a template dir to apply some manifests per user, however it is deprecated.

https://community.ops.io/the_cozma/terraform-alternative-to-the-template-provider-on-apple-m1-mbp-31c8

[hh]

Providers are signed by their developers.
If you'd like to know more about provider signing, you can read about it here:
https://opentofu.org/docs/cli/plugins/signing/
╷
│ Error: Incompatible provider version
│ 
│ Provider registry.opentofu.org/hashicorp/template v2.2.0 does not have a package available for your current platform, darwin_arm64.
│ 
│ Provider releases are separate from OpenTofu CLI releases, so not all providers are available for all platforms. Other versions of this provider may have different
│ platforms supported.
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