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/plugin_kvset_options.go

@@ -0,0 +1,47 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+import (
+	"net/http"
+)
+
+// PluginKVSetOptions contains information on how to store a value in the plugin KV store.
+type PluginKVSetOptions struct {
+	Atomic          bool   // Only store the value if the current value matches the oldValue
+	OldValue        []byte // The value to compare with the current value. Only used when Atomic is true
+	ExpireInSeconds int64  // Set an expire counter
+}
+
+// IsValid returns nil if the chosen options are valid.
+func (opt *PluginKVSetOptions) IsValid() *AppError {
+	if !opt.Atomic && opt.OldValue != nil {
+		return NewAppError(
+			"PluginKVSetOptions.IsValid",
+			"model.plugin_kvset_options.is_valid.old_value.app_error",
+			nil,
+			"",
+			http.StatusBadRequest,
+		)
+	}
+
+	return nil
+}
+
+// NewPluginKeyValueFromOptions return a PluginKeyValue given a pluginID, a KV pair and options.
+func NewPluginKeyValueFromOptions(pluginId, key string, value []byte, opt PluginKVSetOptions) (*PluginKeyValue, *AppError) {
+	expireAt := int64(0)
+	if opt.ExpireInSeconds != 0 {
+		expireAt = GetMillis() + (opt.ExpireInSeconds * 1000)
+	}
+
+	kv := &PluginKeyValue{
+		PluginId: pluginId,
+		Key:      key,
+		Value:    value,
+		ExpireAt: expireAt,
+	}
+
+	return kv, nil
+}