[Tabs] Improve `orientation` prop support

The Tabs component technically supports the orientation prop (values of vertical or horizontal), but the effect it has is to switch between keyDown handlers for ArrowUp+ArrowDown or ArrowLeft+ArrowRight and to alter the aria-orientation prop. The default theme provides no visual support for the vertical orientation, and the orientation prop is entirely undocumented.

• Add theme support for vertical tabs
• Document the orientation prop

[rockchalkwushock]

@dodas @with-heart

Spoke with @segunadebayo this morning and am starting work on this tonight

[dodas]

Example of possible implementation:

// ⁨chakra-ui⁩/⁨packages⁩/⁨theme⁩/src⁩/components⁩/tabs.ts

// Before:
tablist: {
  borderBottom: "2px solid",
  borderColor: "inherit",
},

// After:
tablist: {
  [props.orientation === "vertical" ? "borderRight" : "borderBottom"]: "2px solid",
  borderColor: "inherit",
},

This, and similar orientation-aware definitions would repeat few times across the file, so my question is whether it is readable enough or you guys want to do some type of abstraction/refactoring here?