Check registered application by id

Check registered application by id whether or not exists in collector when agent reconnect to collector.

ApplicationRegisterService.proto

@@ -26,6 +26,9 @@ import "KeyWithIntegerValue.proto";
 
 //register service for ApplicationCode, this service is called when service starts.
 service ApplicationRegisterService {
+    rpc registeredApplicationCheck (RegisteredApplication) returns (ApplicationCheckResult) {
+    }
+    
     rpc applicationCodeRegister (Application) returns (ApplicationMapping) {
     }
 }
@@ -37,3 +40,11 @@ message Application {
 message ApplicationMapping {
     KeyWithIntegerValue application = 1;
 }
+
+message RegisteredApplication {
+    int32 applicationId = 1;
+}
+
+message ApplicationCheckResult {
+    bool existed = 1;
+}