Rewrite split layouts

[rock3r]

In some cases the SplitLayouts don't work correctly when dragging the divider. They also have other issues (see #263 and #277). We should rewrite them, fixing the bugs and allowing nesting. We can look at the core logic of Accompanist's TwoPane component for inspiration.

Basic requirements

• Nesting
• Min/Max sizing in dp
• Divider must be draggable to resize with a mouse
• Draggable area is 1.dp wider than the border
• Divider must not be focusable

Tasks

• [x] Add draggable divider
• [x] Style the divider
• [x] Prevent divider from being focused
• [x] Allow nesting
• [x] Allow resizing with minimum width parameter
• [ ]

[rock3r]

I'm considering rewriting the split layouts based on the core logic of Accompanist's TwoPane component