[expo-video] Add expo-video docs page

[behenate]

Why

Expo-video is missing a docs page.

ENG-11349

How

Renamed the video.mdx to video-av.mdx and assigned video.mdx as expo-video docs page. We should consider doing this the other way around (adding a suffix to expo-video file). Current way might create issues with linking to the docs, eg. if someone wants to redirect people to the latest expo-av video docs so they would link to https://docs.expo.dev/versions/latest/sdk/video/, but the users will be redirected to expo-video docs after SDK 51. I kept it this way in case we believe people should be redirected to expo-video anyways. Let me know what you think about it :)

Created a simple example for expo-video (similar to the expo-av example), which showcases how to use player properties and events.

Test Plan

Tested by running the docs locally

[expo-bot]

📘 Your docs preview website is ready!

[Simek]

Few things to address:

• export missing VolumeEvent, PlayerError, EventName and DRMOptions types
• add return types to PiP methods, they are marked in docs now as returning any
• fix the emit, addListener, removeListener and removeAllListeners params typing - now we output a bogus type for those
• mark as not linkable, or export missing definition for SharedObject

[Simek]

Thanks for the updates! 👍

As discussed offline, we will be working further to improve those docs in near future, but it's definitely a great start!

[amandeepmittal]

Thank you adding this doc and for incorporating those changes