Move all status/alert dialogs into the Left Pane

ts/types/Dialogs.ts

@@ -0,0 +1,6 @@
+export enum Dialogs {
+  None,
+  Update,
+  Cannot_Update,
+  MacOS_Read_Only,
+}

ts/types/SocketStatus.ts

@@ -0,0 +1,8 @@
+// Maps to values found here: https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/readyState
+// which are returned by libtextsecure's MessageReceiver
+export enum SocketStatus {
+  CONNECTING,
+  OPEN,
+  CLOSING,
+  CLOSED,
+}