Native panning

[darabos]

For graph visualizations and for workspaces we implemented our own panning solution. The alternative would be to just let the browser handle panning, same as for any oversized element. Hoped benefits:

• More consistent with the user's environment. E.g. they could use two finger touchpad gestures.
• Less code.
• Better performance. (Wouldn't need a redraw.)
• Playwright could scroll to stuff if needed.