Add support for admin delete.

app/src/main/protowire/Backup.proto

@@ -500,6 +500,7 @@ message ChatItem {
     ViewOnceMessage viewOnceMessage = 18;
     DirectStoryReplyMessage directStoryReplyMessage = 19; // group story reply messages are not backed up
     Poll poll = 20;
+    AdminDeletedMessage adminDeletedMessage = 22;
   }
 
   PinDetails pinDetails = 21; // only set if message is pinned
@@ -900,6 +901,10 @@ message Poll {
   repeated Reaction reactions = 5;
 }
 
+message AdminDeletedMessage {
+  uint64 adminId = 1; // id of the admin that deleted the message
+}
+
 message ChatUpdateMessage {
   // If unset, importers should ignore the update message without throwing an error.
   oneof update {

app/src/main/protowire/JobData.proto

@@ -267,4 +267,10 @@ message CallQualitySurveySubmissionJobData {
 
 message CheckKeyTransparencyJobData{
   bool showFailure = 1;
-}
+}
+
+message AdminDeleteJobData {
+  uint64 messageId = 1;
+  repeated uint64 recipientIds = 2;
+  uint32 initialRecipientCount = 3;
+}