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/data_retention_policy.go

@@ -0,0 +1,88 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+type GlobalRetentionPolicy struct {
+	MessageDeletionEnabled bool  `json:"message_deletion_enabled"`
+	FileDeletionEnabled    bool  `json:"file_deletion_enabled"`
+	BoardsDeletionEnabled  bool  `json:"boards_deletion_enabled"`
+	MessageRetentionCutoff int64 `json:"message_retention_cutoff"`
+	FileRetentionCutoff    int64 `json:"file_retention_cutoff"`
+	BoardsRetentionCutoff  int64 `json:"boards_retention_cutoff"`
+}
+
+type RetentionPolicy struct {
+	ID               string `db:"Id" json:"id"`
+	DisplayName      string `json:"display_name"`
+	PostDurationDays *int64 `db:"PostDuration" json:"post_duration"`
+}
+
+type RetentionPolicyWithTeamAndChannelIDs struct {
+	RetentionPolicy
+	TeamIDs    []string `json:"team_ids"`
+	ChannelIDs []string `json:"channel_ids"`
+}
+
+func (o *RetentionPolicyWithTeamAndChannelIDs) Auditable() map[string]interface{} {
+	return map[string]interface{}{
+		"retention_policy": o.RetentionPolicy,
+		"team_ids":         o.TeamIDs,
+		"channel_ids":      o.ChannelIDs,
+	}
+}
+
+type RetentionPolicyWithTeamAndChannelCounts struct {
+	RetentionPolicy
+	ChannelCount int64 `json:"channel_count"`
+	TeamCount    int64 `json:"team_count"`
+}
+
+func (o *RetentionPolicyWithTeamAndChannelCounts) Auditable() map[string]interface{} {
+	return map[string]interface{}{
+		"retention_policy": o.RetentionPolicy,
+		"channel_count":    o.ChannelCount,
+		"team_count":       o.TeamCount,
+	}
+}
+
+type RetentionPolicyChannel struct {
+	PolicyID  string `db:"PolicyId"`
+	ChannelID string `db:"ChannelId"`
+}
+
+type RetentionPolicyTeam struct {
+	PolicyID string `db:"PolicyId"`
+	TeamID   string `db:"TeamId"`
+}
+
+type RetentionPolicyWithTeamAndChannelCountsList struct {
+	Policies   []*RetentionPolicyWithTeamAndChannelCounts `json:"policies"`
+	TotalCount int64                                      `json:"total_count"`
+}
+
+type RetentionPolicyForTeam struct {
+	TeamID           string `db:"Id" json:"team_id"`
+	PostDurationDays int64  `db:"PostDuration" json:"post_duration"`
+}
+
+type RetentionPolicyForTeamList struct {
+	Policies   []*RetentionPolicyForTeam `json:"policies"`
+	TotalCount int64                     `json:"total_count"`
+}
+
+type RetentionPolicyForChannel struct {
+	ChannelID        string `db:"Id" json:"channel_id"`
+	PostDurationDays int64  `db:"PostDuration" json:"post_duration"`
+}
+
+type RetentionPolicyForChannelList struct {
+	Policies   []*RetentionPolicyForChannel `json:"policies"`
+	TotalCount int64                        `json:"total_count"`
+}
+
+type RetentionPolicyCursor struct {
+	ChannelPoliciesDone bool
+	TeamPoliciesDone    bool
+	GlobalPoliciesDone  bool
+}