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/channel_list.go

@@ -0,0 +1,56 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+type ChannelList []*Channel
+
+func (o *ChannelList) Etag() string {
+
+	id := "0"
+	var t int64 = 0
+	var delta int64 = 0
+
+	for _, v := range *o {
+		if v.LastPostAt > t {
+			t = v.LastPostAt
+			id = v.Id
+		}
+
+		if v.UpdateAt > t {
+			t = v.UpdateAt
+			id = v.Id
+		}
+
+	}
+
+	return Etag(id, t, delta, len(*o))
+}
+
+type ChannelListWithTeamData []*ChannelWithTeamData
+
+func (o *ChannelListWithTeamData) Etag() string {
+
+	id := "0"
+	var t int64 = 0
+	var delta int64 = 0
+
+	for _, v := range *o {
+		if v.LastPostAt > t {
+			t = v.LastPostAt
+			id = v.Id
+		}
+
+		if v.UpdateAt > t {
+			t = v.UpdateAt
+			id = v.Id
+		}
+
+		if v.TeamUpdateAt > t {
+			t = v.TeamUpdateAt
+			id = v.Id
+		}
+	}
+
+	return Etag(id, t, delta, len(*o))
+}