These reports were embedded in the window manager DNA,
but they were always cleared when reading it from files. It's clearer
to just not store the reports in files at all. I also moved the reports
initialization and freeing to the constructor and destructor of the
runtime class.
This is the only place `ReportList` was embedded in DNA, so
after this we can move that to use C++ features if we want.
Pull Request: https://projects.blender.org/blender/blender/pulls/118329
Currently most of the data stored in `wmWindowManager` is runtime
data not saved to files. It's confusing that it's declared in DNA then. That
also prevents us from using C++ features. This commit adds an initial
runtime struct. Moving data there can be done as a separate step.
Initially I wanted to look at moving the `ReportList` system to C++.
The runtime struct has to be defined in the blenkernel module because
the members are (will be) used there in a few places.
Pull Request: https://projects.blender.org/blender/blender/pulls/118157
Hans Goudey