[Development] Merge and Integration status report - 2018.12.22

[Liang Qi]

Merges

* 5.11.3->5.11 merges are done, including qt5, so 5.11.3 branch could be nuked.
* 5.12.0->5.12, qt5 one https://codereview.qt-project.org/#/c/248857/ is ongoing
* 5.11->5.12, still missing qtwebengine and qt5
* 5.12->dev, need to be done after new year

Integrations

* 5.12 is healthy
* dev got latest submodule update merged in https://codereview.qt-project.org/#/c/174522/ this morning.

Happy new year!

--Liang