[docs] Expo Router: add docs for missing API reference (#23355)

# Why

- As mentioned by @amandeepmittal, we need docs for the hooks API
https://github.com/expo/expo/pull/23243

# How

- Adde

[docs] Expo Router: add docs for missing API reference (#23355)

# Why

- As mentioned by @amandeepmittal, we need docs for the hooks API
https://github.com/expo/expo/pull/23243

# How

- Added API ref and ported docs.
- Added a URL switching component to help users understand how different
runtimes work.

<img width="643" alt="Screenshot 2023-07-06 at 5 34 02 PM"
src="https://github.com/expo/expo/assets/9664363/19e824ef-d22e-460e-9a2a-08fc956e872a">
<img width="639" alt="Screenshot 2023-07-06 at 5 34 08 PM"
src="https://github.com/expo/expo/assets/9664363/a813891c-2fae-4179-b379-e1bc0ed39b01">
<img width="636" alt="Screenshot 2023-07-06 at 5 34 16 PM"
src="https://github.com/expo/expo/assets/9664363/db96627f-93b1-4da0-a148-0d86eb59cd29">
<img width="637" alt="Screenshot 2023-07-06 at 5 34 21 PM"
src="https://github.com/expo/expo/assets/9664363/38151aeb-7f62-480d-ac82-b37d05d3d962">

---------

Co-authored-by: Aman Mittal <[email protected]>
Co-authored-by: Bartosz Kaszubowski <[email protected]>

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