Make an example for bevy_ui gizmos layout overlay

## What problem does this solve or what need does it fill?

This can help us track regressions with the tool and at the same time have an overview of the currently supported features on the tool. At the same time, the example would show of many things on Ui, like scale, init with given scale or rotation (see #12576 ) and maybe how it handle with borders

## What solution would you like?

An example in examples/dev_tools demonstrating everything this tool currently supports:
- Ui Scale
- Borders with radius
- A bar with overflow set (the current behavior is showing everything that is not hidden, even if we can't see the thing)

And maybe remove this feature from our current [ui](https://github.com/bevyengine/bevy/blob/main/examples/ui/ui.rs) example

In the future, if we support multiple windows with gizmos in a feasible way, we can have multiple windows on this example to show this working too (maybe not needed)

## What alternative(s) have you considered?

We can just add this feature to some of our examples to test every now and then.