Support Sliding windows and fixed main pane

[rushikb]

Long-time roam user making the switch and absolutely love this plugin. One thing that I was hoping to replicate was a way to create a fixed "main pane" and use sliding panes for everything else— this was something I'd become hopelessly attached to— and which I think might be useful for a lot of others too.

[gimbo]

Possibly a duplicate of https://github.com/deathau/sliding-panes-obsidian/issues/8