Didn't commit all the changes where it wants to initialize a struct
with `{}`. Should be reviewed in a separate PR.
Option `IgnoreArrays` enabled for now to be conservative, can be
disabled to see if it proposes more useful changes.
Also fixed manually a handful of other missing initializations / moved
some from constructors.
Convert method signature parameters to const where it is possible
# Conflicts:
# drivers/gles3/rasterizer_canvas_gles3.cpp
# drivers/gles3/rasterizer_canvas_gles3.h
# editor/plugins/animation_state_machine_editor.cpp
# editor/plugins/animation_state_machine_editor.h
