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/builtin.go

@@ -0,0 +1,9 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+func NewBool(b bool) *bool       { return &b }
+func NewInt(n int) *int          { return &n }
+func NewInt64(n int64) *int64    { return &n }
+func NewString(s string) *string { return &s }