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/initial_load.go

@@ -0,0 +1,14 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+type InitialLoad struct {
+	User        *User             `json:"user"`
+	TeamMembers []*TeamMember     `json:"team_members"`
+	Teams       []*Team           `json:"teams"`
+	Preferences Preferences       `json:"preferences"`
+	ClientCfg   map[string]string `json:"client_cfg"`
+	LicenseCfg  map[string]string `json:"license_cfg"`
+	NoAccounts  bool              `json:"no_accounts"`
+}