Sync LLChatBar with alchemy's LLChatBar and LLChatUtilities

Stops typing anim on chatbar focus loss
Makes a couple classes final
Adds checkChatVolume and canSendChannel to RlvActions
Updates other bits of Rlv, but adds no functionality

indra/newview/app_settings/settings_ascent.xml

@@ -212,6 +212,17 @@
       <key>Value</key>
       <integer>1</integer>
     </map>
+    <key>AlchemyNearbyChatChannel</key>
+    <map>
+      <key>Comment</key>
+      <string>Chat channel used for sending nearby chat from the viewer</string>
+      <key>Persist</key>
+      <integer>0</integer>
+      <key>Type</key>
+      <string>S32</string>
+      <key>Value</key>
+      <integer>0</integer>
+    </map>
     <key>AlchemyRainbowEffects</key>
     <map>
       <key>Comment</key>