feat: Support terraform import blocks

[simar7]

As of Terraform 1.5, support has been added for import blocks.

https://github.com/hashicorp/terraform/blob/v1.5/CHANGELOG.md#150-june-12-2023
https://developer.hashicorp.com/terraform/language/import

Today we do not support this, therefore scanning any file that has an import block will not be classified as a terraform config file.

$ trivy config .
2023-06-16T15:54:47.536-0600    INFO    Misconfiguration scanning is enabled
2023-06-16T15:54:48.037-0600    INFO    Detected config files: 0
$ cat main.tf 
import {
  to = aws_instance.example
  id = "i-abcd1234"
}

resource "aws_instance" "example" {
  name = "hashi"
}