multi-window sessions

[KiaraGrouwstra]

Is your feature request related to a problem? Please describe.

I tend to multi-task, having browser windows in multiple workspaces.
Nyxt supports having multiple windows, and can restore buffers from a previous session.
However, restoring buffers from a previous session currently opens them in one and the same window.

Describe the solution you'd like
Have Nyxt restore multiple windows from the last session rather than restoring them as a single window.

Describe alternatives you've considered
stick with legacy browsers

Additional context
I reboot sometimes.

[aadcg]

@KiaraGrouwstra thanks for the idea and interest.

It shouldn't be hard to implement, PRs welcome :)