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/user_count.go

@@ -0,0 +1,26 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+// Options for counting users
+type UserCountOptions struct {
+	// Should include users that are bots
+	IncludeBotAccounts bool
+	// Should include deleted users (of any type)
+	IncludeDeleted bool
+	// Exclude regular users
+	ExcludeRegularUsers bool
+	// Only include users on a specific team. "" for any team.
+	TeamId string
+	// Only include users on a specific channel. "" for any channel.
+	ChannelId string
+	// Restrict to search in a list of teams and channels
+	ViewRestrictions *ViewUsersRestrictions
+	// Only include users matching any of the given system wide roles.
+	Roles []string
+	// Only include users matching any of the given channel roles, must be used with ChannelId.
+	ChannelRoles []string
+	// Only include users matching any of the given team roles, must be used with TeamId.
+	TeamRoles []string
+}