Themes are loaded from the Themes directory (under the Chatterino directory, so %APPDATA%/Chatterino2/Themes).
Themes are json files (see the built in themes as an example).
After importing a theme, you must restart Chatterino for it to show up in the settings
This change enforces strict include grouping using IncludeCategories
In addition to adding this to the .clang-format file and applying it in the tests/src and src directories, I also did the following small changes:
In ChatterSet.hpp, I changed lrucache to a <>include
In Irc2.hpp, I change common/SignalVector.hpp to a "project-include"
In AttachedWindow.cpp, NativeMessaging.cpp, WindowsHelper.hpp, BaseWindow.cpp, and StreamerMode.cpp, I disabled clang-format for the windows-includes
In WindowDescriptors.hpp, I added the missing vector include. It was previously not needed because the include was handled by another file that was previously included first.
clang-format minimum version has been bumped, so Ubuntu version used in the check-formatting job has been bumped to 22.04 (which is the latest LTS)
