feat(stackit-object-storage): Implement IAM policies for credential access control

[HartmannVolker]

Migration docs for stackit-object-storage module:

Provider

Same as in stackit-state-bucket module

Move resources

moved {
  from = module.object_storage_bucket.stackit_objectstorage_credentials_group.credentials_group
  to   = module.object_storage_bucket.stackit_objectstorage_credentials_group.terraform_credentials_group
}

⚠️ This change will break your existing credentials

Migration docs stackit-state-bucket module:

Provider:

Add this to required_providers:

    aws = {
      source  = "hashicorp/aws"
      version = ">=6.28.0"
    }

Add the aws provider config:

provider "aws" {
  region                      = "eu01"
  skip_credentials_validation = true
  skip_region_validation      = true
  skip_requesting_account_id  = true

  access_key = module.terraform_backend.access_key
  secret_key = module.terraform_backend.secret_access_key

  endpoints {
    s3 = "https://object.storage.eu01.onstackit.cloud"
  }
}

Move resources

moved {
  from = module.terraform_backend.module.object_storage.stackit_objectstorage_credentials_group.credentials_group
  to   = module.terraform_backend.module.object_storage.stackit_objectstorage_credentials_group.terraform_credentials_group
}

moved {
  from = module.terraform_backend.module.object_storage.stackit_objectstorage_credential.credential["default"]
  to   = module.terraform_backend.module.object_storage.stackit_objectstorage_credential.terraform_credentials
}

moved {
  from =  module.terraform_backend.module.object_storage.stackit_objectstorage_bucket.state_bucket
  to   =  module.terraform_backend.module.object_storage.stackit_objectstorage_bucket.bucket
}