worker: introduce MoveMessages type

Introduce a MoveMessages worker message to use for improved message
moving in subsequent patches.

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Acked-by: Robin Jarry <robin@jarry.cc>

worker/types/messages.go

@@ -165,6 +165,12 @@ type CopyMessages struct {
 	Uids        []uint32
 }
 
+type MoveMessages struct {
+	Message
+	Destination string
+	Uids        []uint32
+}
+
 type AppendMessage struct {
 	Message
 	Destination string
@@ -231,6 +237,12 @@ type MessagesCopied struct {
 	Uids        []uint32
 }
 
+type MessagesMoved struct {
+	Message
+	Destination string
+	Uids        []uint32
+}
+
 type ModifyLabels struct {
 	Message
 	Uids   []uint32