Move applicationKeypad into core service

src/common/Types.d.ts

@@ -152,6 +152,7 @@ export interface IMarker extends IDisposable {
 
 export interface IDecPrivateModes {
   applicationCursorKeys: boolean;
+  applicationKeypad: boolean;
   origin: boolean;
   wraparound: boolean; // defaults: xterm - true, vt100 - false
 }