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/model/usage.go

@@ -0,0 +1,34 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+type PostsUsage struct {
+	Count int64 `json:"count"`
+}
+
+type StorageUsage struct {
+	Bytes int64 `json:"bytes"`
+}
+
+type TeamsUsage struct {
+	Active        int64 `json:"active"`
+	CloudArchived int64 `json:"cloud_archived"`
+}
+
+var InstalledIntegrationsIgnoredPlugins = map[string]struct{}{
+	PluginIdPlaybooks:     {},
+	PluginIdFocalboard:    {},
+	PluginIdApps:          {},
+	PluginIdCalls:         {},
+	PluginIdNPS:           {},
+	PluginIdChannelExport: {},
+}
+
+type InstalledIntegration struct {
+	Type    string `json:"type"` // "plugin" or "app"
+	ID      string `json:"id"`
+	Name    string `json:"name"`
+	Version string `json:"version"`
+	Enabled bool   `json:"enabled"`
+}