This commit introduces a new wrapper, CustomUi, which is used to
implement custom methods on top of eframe::egui::Ui.
The default ui::add_sized method always has the text in a label
centered, which is not desirable for a status bar where the layout
should be ltr.
A new function CustomUi::add_sized_left_to_right has been added to
ensure that labels can be truncated with a custom width (which requires
allocate_ui_with_layout), while also retaining the ability for the text
to be aligned to the left rather than the center of the allocated
layout.
LGUG2Z