✨ new tfgen go package to generate hcl code

This is the first step to start writing automation code to onboard integration into Mondoo. `tfgen` is a primitive that will help us write HCL code in plain Go programming language.

For example, here is the translation of this code that integrates a Google project into the Mondoo platform.

> Code: https://registry.terraform.io/providers/mondoohq/mondoo/latest/docs/resources/integration_gcp

```go
mondooProvider, err := tfgen.NewProvider("mondoo", tfgen.HclProviderWithAttributes(
	map[string]interface{}{
		"space": "hungry-poet-123456",
	},
)).ToBlock()
googleProvider, err := tfgen.NewProvider("google", tfgen.HclProviderWithAttributes(
	map[string]interface{}{
		"project": "prod-project-123",
		"region":  "us-central1",
	},
)).ToBlock()
googleServiceAccountResource, err := tfgen.NewResource("google_service_account",
	"mondoo", tfgen.HclResourceWithAttributesAndProviderDetails(
		map[string]interface{}{
			"account_id":   "mondoo-integration",
			"display_name": "Mondoo service account",
		}, nil,
	)).ToResourceBlock()
googleServiceAccountKey, err := tfgen.NewResource("google_service_account_key",
	"mondoo", tfgen.HclResourceWithAttributesAndProviderDetails(
		map[string]interface{}{
			"service_account_id": tfgen.CreateSimpleTraversal("google_service_account", "mondoo", "name"),
		}, nil,
	)).ToResourceBlock()
mondooIntegrationGCP, err := tfgen.NewResource("mondoo_integration_gcp",
	"production", tfgen.HclResourceWithAttributesAndProviderDetails(
		map[string]interface{}{
			"name":       "Production account",
			"project_id": "prod-project-123",
			"credentials": map[string]interface{}{
				"private_key": tfgen.NewFuncCall(
					"base64decode", tfgen.CreateSimpleTraversal("google_service_account_key", "mondoo", "private_key")),
			},
		}, nil,
	)).ToResourceBlock()

blocksOutput := tfgen.CreateHclStringOutput(
	tfgen.CombineHclBlocks(
		mondooProvider,
		googleProvider,
		googleServiceAccountResource,
		googleServiceAccountKey,
		mondooIntegrationGCP,
	)...,
)
```

This will result in the following HCL code:
```hcl
provider "mondoo" {
  space = "hungry-poet-123456"
}

provider "google" {
  project = "prod-project-123"
  region  = "us-central1"
}

resource "google_service_account" "mondoo" {
  account_id   = "mondoo-integration"
  display_name = "Mondoo service account"
}

resource "google_service_account_key" "mondoo" {
  service_account_id = google_service_account.mondoo.name
}

resource "mondoo_integration_gcp" "production" {
  credentials = {
    private_key = base64decode(google_service_account_key.mondoo.private_key)
  }
  name       = "Production account"
  project_id = "prod-project-123"
}
```

Signed-off-by: Salim Afiune Maya <[email protected]>