UI: Overhaul Boolean widget, Improve SelectUI/Panel UX

Moves logic to \<InputBoolUI> so that it's easily re-usable as a checkbox for other widgets
Adds a deprecation warning for label2 on Widget_BoolUI, it should be replaced with the new text option
Dragging to make checkbox share a similar state when you drag over them should work with more areas now that more things will use the same underlying widget instead of duplicated code. (Only WidgetBoolUI, Widget_ToggleUI, and SelectUI (search enum, choices) with this PR)

expand Makes the widget use as much space as possible (horizontally)
icon Uses a material-symbols-outlined icon name (Not sure how to type this correctly so it's just a string, but displaying all the icon names would be cool)
display Sets the way the widget is displayed
- check gives you a normal checkbox, with the text/icon to the right
- button gives you a toggle-able button similar to how form.choices() looks.
Thing to note is that the display function changes how the undefined state of expand is interpreted, with 'check' using an expand = true by default, and 'button' using an expand = false by default.

Use InputBoolUI
Clicking on any non-button part of the pop-up no longer closes it.
Un-focuses the underlying text input when the menu closes. Fixes the pop-up opening when you un-focus and re-focus the window when the pop-up is active, also just feels nicer. Probably really only hurt the experience for people who use focus window under mouse, like me. uvu
Closes the pop-up when you are a certain distance away from one of the edges. Gives people a bit of slack with moving their mouse to/in the pop-up
You can now drag to set multiple entries to the same state instead of having to click each one individually.
Fake the gaps between entries. Follows Fitt's law by having no dead areas between the part of the buttons the user can click.

Make the header collapse/expand panels, buttons should preventDefault/stopPropagation in onMouseDown to prevent themselves from triggering this if they're in the header.
Holding left mouse and dragging over the headers of panels now quickly expands/collapses them.

rvion / CushyStudio