This cherrypicks most of commit d90a9ab70c7ef73577775f0abed8552907899f75
It doesn't actually remove Kernel/API/KeyCode.h though, since we still
need that :^)
Patch created by running (in zsh, where the `${=foo}` syntax is needed
to tell zsh to convert space-separated strings into separate args):
files=$(git show --name-only --pretty='' d90a9ab70c7e |
rg -v 'CMakeLists.txt|KeyCode.h' | tr '\n' ' ')
git show d90a9ab70c7e -- ${=files} | git apply -3 -
Now that all input events are handled by LibWebView, replace the IPCs
which send the fields of Web::KeyEvent / Web::MouseEvent individually
with one IPC per event type (key or mouse).
We can also replace the ad-hoc queued input structure with a smaller
struct that simply holds the tranferred Web::KeyEvent / Web::MouseEvent.
In the future, we can also adapt Web::EventHandler to use these structs.
