Create reconversion guide

[jodator]

📝 Provide a description of requested docs changes

We need a guide for the new reconversion concepts by covering cases from #7956 (comment).

[jodator]

I've came to this sample feature to showcase reconversion:

The premise is to showcase use-cases:

• reconversion of the complex view as one (and sell it as a funcitonal render)
• rendering custom UI elements inside the widget

The problem, for now, is that the above code builds on top of other similar guides (element-to-element conversion and box widget).

[jodator]

Closed with daedd3c.