v8.0 module release (#22975)

https://mattermost.atlassian.net/browse/MM-52079

```release-note
We upgrade the module version to 8.0. The new module path is github.com/mattermost-server/server/v8.
```


Co-authored-by: Doug Lauder <wiggin77@warpmail.net>

server/plugin/environment_test.go

@@ -0,0 +1,98 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package plugin
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/mattermost/mattermost-server/server/v8/model"
+	"github.com/mattermost/mattermost-server/server/v8/platform/shared/mlog"
+)
+
+func TestAvailablePlugins(t *testing.T) {
+	dir, err1 := os.MkdirTemp("", "mm-plugin-test")
+	require.NoError(t, err1)
+	t.Cleanup(func() {
+		os.RemoveAll(dir)
+	})
+
+	testLogger, _ := mlog.NewLogger()
+	env := Environment{
+		pluginDir: dir,
+		logger:    testLogger,
+	}
+
+	t.Run("Should be able to load available plugins", func(t *testing.T) {
+		bundle1 := model.BundleInfo{
+			Manifest: &model.Manifest{
+				Id:      "someid",
+				Version: "1",
+			},
+		}
+		err := os.Mkdir(filepath.Join(dir, "plugin1"), 0700)
+		require.NoError(t, err)
+		defer os.RemoveAll(filepath.Join(dir, "plugin1"))
+
+		path := filepath.Join(dir, "plugin1", "plugin.json")
+		manifestJSON, jsonErr := json.Marshal(bundle1.Manifest)
+		require.NoError(t, jsonErr)
+		err = os.WriteFile(path, manifestJSON, 0644)
+		require.NoError(t, err)
+
+		bundles, err := env.Available()
+		require.NoError(t, err)
+		require.Len(t, bundles, 1)
+	})
+
+	t.Run("Should not be able to load plugins without a valid manifest file", func(t *testing.T) {
+		err := os.Mkdir(filepath.Join(dir, "plugin2"), 0700)
+		require.NoError(t, err)
+		defer os.RemoveAll(filepath.Join(dir, "plugin2"))
+
+		path := filepath.Join(dir, "plugin2", "manifest.json")
+		err = os.WriteFile(path, []byte("{}"), 0644)
+		require.NoError(t, err)
+
+		bundles, err := env.Available()
+		require.NoError(t, err)
+		require.Len(t, bundles, 0)
+	})
+
+	t.Run("Should not be able to load plugins without a manifest file", func(t *testing.T) {
+		err := os.Mkdir(filepath.Join(dir, "plugin3"), 0700)
+		require.NoError(t, err)
+		defer os.RemoveAll(filepath.Join(dir, "plugin3"))
+
+		bundles, err := env.Available()
+		require.NoError(t, err)
+		require.Len(t, bundles, 0)
+	})
+
+	t.Run("Should not load bundles on blocklist", func(t *testing.T) {
+		bundle := model.BundleInfo{
+			Manifest: &model.Manifest{
+				Id:      "playbooks",
+				Version: "1",
+			},
+		}
+		err := os.Mkdir(filepath.Join(dir, "plugin4"), 0700)
+		require.NoError(t, err)
+		defer os.RemoveAll(filepath.Join(dir, "plugin4"))
+
+		path := filepath.Join(dir, "plugin4", "plugin.json")
+		manifestJSON, jsonErr := json.Marshal(bundle.Manifest)
+		require.NoError(t, jsonErr)
+		err = os.WriteFile(path, manifestJSON, 0644)
+		require.NoError(t, err)
+
+		bundles, err := env.Available()
+		require.NoError(t, err)
+		require.Len(t, bundles, 0)
+	})
+}