Add Gizmo component

[marklundin]

This PR adds a new controlled <Gizmo/> component for modifying an <Entity/> components position, rotation and scale

Usage:

import { Entity } from "@playcanvas/react"
import { Gizmo } from "@playcanvas/react/components"

export function Main() {
  // The selected entity
  const [selected, setSelected] = useState(null)

   // The transform
  const [transform, setTransform] = useState({
    position: [0, 0, 0],
    rotation: [0, 0, 0],
    scale: [1, 1, 1]
  }) 

  return (<>
    <Entity {...transform} onClick={e => seSelected(e)}>
      <Render type="sphere" />
    <Entity/>
    { selected && <Gizmo nodes={[selected]} onCommit={t => setTransform(t)}/> } // Only render the gizmo when something is selected
  </>)
}

TODO:

• Docs
• Tests

[changeset-bot]

🦋 Changeset detected

Latest commit: 679d881

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@playcanvas/react	Minor
@playcanvas/blocks	Patch

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commit: 679d881