Wt

In #12174 we had added a script that runs a very basic test, navigating over the widget gallery. This is sufficient to catch a certain class of JS errors, which was the reason for implementing it at the time.

We now however see the need for better UI tests, as much of the layouting has gotten overhauls, and functionality was changed such that the previous detection is far from sufficient.

To this end we will implement a framework using Selenium. No proper C++ binding exists for this, sadly, so we will fall back to the Python one (like previously). However, instead of writing all our test in Python, we will build a framework purely in C++. The C++ code will then be "translated" to Python so that its interpreter can be used to contact Selenium.