Add ImageExport renderer for playwright-dotnet

[kMutagene]

Description

As plotly.js, the underlying library that Plotly.NET is using needs an environment that can execute javascript to render images programmatically.

https://github.com/microsoft/playwright-dotnet seems to be another stable, mature option for automating tasks on a headless browser.

Pointers

• A reference implementation for this using PuppeteerSharp can be seen here