Yeet away current DefaultInputPlugin implementation and replace it with proper one

[taishi-sama]

Sub-issue of #19741

Upstreamed version of DefaultInputPlugin inside PanOrbitCamera is not sufficient for future Bevy Editor's use cases.

Current version of collective proposal

• Move current version of DefaultInputPlugin into examples folder as example how to replace input plugin for PanOrbitCamera.
• Implement new version of DefaultInputPlugin based on window-picking Drag observers
  • New implementation should support rebindind/unbinding buttons for camera movement.

Additional context

Further discussions are welcome in #editor-dev

[laundmo]

I'm messing around with a drag observers based input plugin right now, its going okay. Already found an issue with window observers.

Not saying i'll do a PR for sure, but i'm testing for now

[laundmo]

Okay, i got my messing around pushed to https://github.com/laundmo/bevy/tree/pan_orbit_picking_inputs

also includes free bonus window picking fix (how did i never notice, i use window picking a lot)

[alice-i-cecile]

The full solution is to finalize #23016.