Add option to not send read receipts.

Addresses element-hq/element-web#2527.

The side effect of this is that notifications remain stuck. Because the RR isn't sent, the unread notification stays on the client. This also ends up affecting riot-android, and likely riot-ios.

Signed-off-by: Travis Ralston <travpc@gmail.com>

src/components/structures/TimelinePanel.js

@@ -514,6 +514,7 @@ var TimelinePanel = React.createClass({
         const cli = MatrixClientPeg.get();
         // if no client or client is guest don't send RR or RM
         if (!cli || cli.isGuest()) return;
+        if (UserSettingsStore.getSyncedSetting('dontSendReadReceipts', false)) return;
 
         let shouldSendRR = true;
 

src/components/structures/UserSettings.js

@@ -63,6 +63,10 @@ const SETTINGS_LABELS = [
         id: 'autoplayGifsAndVideos',
         label: 'Autoplay GIFs and videos',
     },
+    {
+        id: 'dontSendReadReceipts',
+        label: "Don't send read receipts"
+    },
     {
         id: 'hideReadReceipts',
         label: 'Hide read receipts',