add qmqtt submodule

.gitmodules

@@ -7,3 +7,6 @@
 [submodule "libs/thirdParty/tiny-AES128-C"]
 	path = libs/thirdParty/tiny-AES128-C
 	url = https://github.com/bkueng/tiny-AES128-C.git
+[submodule "libs/thirdParty/qmqtt"]
+	path = libs/thirdParty/qmqtt
+	url = https://github.com/emqtt/qmqtt.git

qmqtt @ 2e5c64ed

+Subproject commit 2e5c64ed4ab1771f8d9c9e508672f1468803a112

qgroundcontrol.pro

@@ -131,6 +131,10 @@ WindowsBuild {
     QMAKE_TARGET_PRODUCT        = "$${QGC_APP_NAME}"
 }
 
+include($$PWD/libs/thirdParty/qmqtt/src/mqtt/mqtt.pri)
+HEADERS += $$PUBLIC_HEADERS $$PRIVATE_HEADERS
+
+
 #
 # Plugin configuration
 #