Boards data retention (#19262)

* add Boards to DataRetention, add hook for data retention

* remove replaces

* update hook to remove parameter

* add boards data retention to telemetry

* fix unit test

* update test, update hooks

* update RunDataRetention server version

* put behind a feature flag

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

model/feature_flags.go

@@ -71,6 +71,9 @@ type FeatureFlags struct {
 	// Enable inline post editing
 	InlinePostEditing bool
 
+	// Enable DataRetention for Boards
+	BoardsDataRetention bool
+
 	NormalizeLdapDNs bool
 }
 
@@ -96,6 +99,7 @@ func (f *FeatureFlags) SetDefaults() {
 	f.ResendInviteEmailInterval = ""
 	f.InviteToTeam = "none"
 	f.InlinePostEditing = false
+	f.BoardsDataRetention = false
 	f.NormalizeLdapDNs = false
 }