Pin mode for drawer (make drawer part of UI rather than slide over)

[dimitrieh]

Description

Add pin mode functionality to make the drawer part of the UI rather than a slide over.

Context

From PR #6234 description, mentioned to @gstout52.

Acceptance Criteria

• [ ] Implement pin mode for drawer

[dimitrieh]

@gstout52 this is still a strong recommendation for both FlowFuse env and in immersive editor