[API CHANGE] Add a new API call for sysadm/update: action="applyupdate".

This takes no other inputs, and returns the following:
{
"applyupdate" : {
  "result" : "rebooting to apply updates"
  }
}

src/server/WebBackend.cpp

@@ -650,6 +650,10 @@ RestOutputStruct::ExitCode WebSocket::EvaluateSysadmUpdateRequest(const QJsonVal
 	ok = true;
 	out->insert("stopupdate", sysadm::Update::stopUpdate() );
 
+      }else if(act=="applyupdate"){
+	ok = true;
+	out->insert("applyupdate", sysadm::Update::applyUpdates() );
+
       }else if(act=="listsettings"){
 	ok = true;
 	out->insert("listsettings", sysadm::Update::readSettings() );

src/server/library/sysadm-update.cpp

@@ -267,6 +267,12 @@ QJsonObject Update::stopUpdate() {
   return ret;
 }
 
+QJsonObject Update::applyUpdates(){
+  QJsonObject ret;
+  QProcess::startDetached("pc-updatemanager startupdate");
+  ret.insert("result","rebooting to complete updates");
+  return ret;
+}
 //SETTINGS OPTIONS
 QJsonObject Update::readSettings(){
   QJsonObject ret;

src/server/library/sysadm-update.h

@@ -25,6 +25,7 @@ public:
 	//Start/stop update routine
 	static QJsonObject startUpdate(QJsonObject);
 	static QJsonObject stopUpdate();
+	static QJsonObject applyUpdates();
 	//Read/write update settings
 	static QJsonObject readSettings();
 	static QJsonObject writeSettings(QJsonObject);