Move components from reakit to radix-ui

[tommoor]

Reakit is dead, Radix won.

Sometimes we bet on the wrong frameworks and that's definitely what happened here – shadcn provides some great boilerplate to make moving across easier, combining the parts of Radix into usable UI components. We should move Outline's components one by one to radix, in particular:

• InputSelect
• Input
• Button
• ArrowKeyNavigation
• Modal
• Popover
• VisuallyHidden
• ContextMenu

The context menu will be a relatively large undertaking and as such, should be left until last.

[linear]

OLN-222 Move components from `reakit` to `radix-ui`