Return kms encryption for ArgoCD configurations

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During upgrading of sak-argocd module, kms enc/decr functionality was removed.
This functionality should be done in other ways as it was done here - sak-argocd main.tf

Some modules like sak-prometheus still use it. (but without kms encrypting at all)

[wallhided]

My status:

1. Since argocd project get rid of python in their docker images - old integration with python script which decrypts application configs during "generation" no longer works. Currently there are no options of using old script, except re-build base ArgoCD image and keep it in public repo.
2. There additional options like SOPS with using AWS KMS for encryption, but unfortunately there are following problems with implementing such feature:

• User should manually encrypt file with sops utility. (Currently, there are no options to do that via terraform)
• Decryption on fly happens only for file with helm values, we provide single file with application configuration with all helm parameters. This approach requires many steps for user to do.

I'm freezing this ticket, since there are no viable options for now.