Migrate provider code to internal/ package

Reference: https://developer.hashicorp.com/terraform/plugin/best-practices/interacting-with-providers

This change moves the provider code from the exported `tfe` package to the `internal/provider` package, which is a recommended practice since the compatibility and versioning of a provider is generally only considered for the interface with Terraform and practitioner configurations, not with other potential Go modules. The recommended way for other code to interact with a provider is via Terraform CLI's machine-readable interfaces, e.g. JSON outputs, and worst case gRPC.

The internalized code structure has been used across many official provider codebases already for a long time, including the utility providers, `hashicorp/aws`, and `hashicorp/azurerm`.

Author: bflad

.github/actions/test-provider-tfe/action.yml

@@ -103,7 +103,7 @@ runs:
         GITHUB_WORKSPACE_BRANCH: "test"
         GITHUB_TOKEN: "${{ inputs.testing-github-token }}"
         MOD_PROVIDER: github.com/hashicorp/terraform-provider-tfe
-        MOD_TFE: github.com/hashicorp/terraform-provider-tfe/tfe
+        MOD_TFE: github.com/hashicorp/terraform-provider-tfe/internal/provider
         MOD_VERSION: github.com/hashicorp/terraform-provider-tfe/version
       run: |
         gotestsum --junitfile summary.xml --format short-verbose -- $MOD_PROVIDER $MOD_TFE $MOD_VERSION -v -timeout=30m -run "${{ steps.test_split.outputs.run }}"

tfe/agent_pool_helpers.go renamed to internal/provider/agent_pool_helpers.go

@@ -1,7 +1,7 @@
 // Copyright (c) HashiCorp, Inc.
 // SPDX-License-Identifier: MPL-2.0
 
-package tfe
+package provider
 
 import (
 	"fmt"

tfe/client_mock_workspaces.go renamed to internal/provider/client_mock_workspaces.go

@@ -1,7 +1,7 @@
 // Copyright (c) HashiCorp, Inc.
 // SPDX-License-Identifier: MPL-2.0
 
-package tfe
+package provider
 
 import (
 	"context"

tfe/config_unix.go renamed to internal/provider/config_unix.go

@@ -4,7 +4,7 @@
 //go:build !windows
 // +build !windows
 
-package tfe
+package provider
 
 import (
 	"errors"

tfe/config_windows.go renamed to internal/provider/config_windows.go

@@ -4,7 +4,7 @@
 //go:build windows
 // +build windows
 
-package tfe
+package provider
 
 import (
 	"path/filepath"

tfe/data_source_agent_pool.go renamed to internal/provider/data_source_agent_pool.go

@@ -1,7 +1,7 @@
 // Copyright (c) HashiCorp, Inc.
 // SPDX-License-Identifier: MPL-2.0
 
-package tfe
+package provider
 
 import (
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"

tfe/data_source_agent_pool_test.go renamed to internal/provider/data_source_agent_pool_test.go

@@ -1,7 +1,7 @@
 // Copyright (c) HashiCorp, Inc.
 // SPDX-License-Identifier: MPL-2.0
 
-package tfe
+package provider
 
 import (
 	"fmt"

tfe/data_source_github_app_installation.go renamed to internal/provider/data_source_github_app_installation.go

@@ -1,6 +1,6 @@
 // Copyright (c) HashiCorp, Inc.
 // SPDX-License-Identifier: MPL-2.0
-package tfe
+package provider
 
 import (
 	"context"

tfe/data_source_github_app_installation_test.go renamed to internal/provider/data_source_github_app_installation_test.go

@@ -1,12 +1,13 @@
 // Copyright (c) HashiCorp, Inc.
 // SPDX-License-Identifier: MPL-2.0
 
-package tfe
+package provider
 
 import (
 	"fmt"
-	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
 	"testing"
+
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
 )
 
 func testAccTFEGHAInstallationDataSourcePreCheck(t *testing.T) {

tfe/data_source_ip_ranges.go renamed to internal/provider/data_source_ip_ranges.go

@@ -1,7 +1,7 @@
 // Copyright (c) HashiCorp, Inc.
 // SPDX-License-Identifier: MPL-2.0
 
-package tfe
+package provider
 
 import (
 	"fmt"