refactor: organize plugin to support multiple services (#1)

Co-authored-by: Michael Li <michael.li@hashicorp.com>

testing/testdata/host/main.tf

@@ -0,0 +1,11 @@
+# Copyright (c) HashiCorp, Inc.
+# SPDX-License-Identifier: MPL-2.0
+
+terraform {
+  required_providers {
+    aws = {
+      source  = "hashicorp/aws"
+      version = "~> 3.0"
+    }
+  }
+}