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/audit.go

@@ -0,0 +1,14 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+type Audit struct {
+	Id        string `json:"id"`
+	CreateAt  int64  `json:"create_at"`
+	UserId    string `json:"user_id"`
+	Action    string `json:"action"`
+	ExtraInfo string `json:"extra_info"`
+	IpAddress string `json:"ip_address"`
+	SessionId string `json:"session_id"`
+}