Support remote backend block in definition.json for spk infra scaffold

[yradsmikham]

As a:
Developer

I want:
to add backend variables to definition.json if they exists in Terraform templates

So that:
spk can support remote backend configuration

Describe the solution you'd like:

• spk infra scaffold should scan for the existence of a backend.tf or backend.tfvars
• Parse and generate backend variables to be part of definition.json

Describe alternatives you've considered:

Additional context:

{
    name: "discovery-cluster",
    source: "https://github.com/fabrikam/bedrock",
    template: "cluster/environments/fabrikam-single-keyvault",
    version: "v1.0",

    variables: {
        backend_storage_account_name: "tfstate"
        backend_container_name: "discoveryservice",
        agent_vm_count: 16,
        gitops_ssh_url: "[email protected]:fabrikam/discovery-cluster-manifests.git"
    }
}

or

{
    name: "discovery-cluster",
    source: "https://github.com/fabrikam/bedrock",
    template: "cluster/environments/fabrikam-single-keyvault",
    version: "v1.0",
    backend: {
        backend_storage_account_name: "tfstate"
        backend_container_name: "discoveryservice",
    }
    variables: {
        agent_vm_count: 16,
        gitops_ssh_url: "[email protected]:fabrikam/discovery-cluster-manifests.git"
    }
}

Does this require updates to documentation?:
Yes