Playback a video stream redirect changes

[pglowacky]

We'll need to add to the playback a video docs that when you request to get the playback URL, the response will perform a 302 redirect to the address of the nearest Catalyst location node. This behavior is captured in this Discord thread: https://discord.com/channels/423160867534929930/992554008776540180/1021400715446464612

Users will need to write logic in order to handle the redirection, although most players and browsers should follow the redirects automatically.

[pglowacky]

@adamsoffer and I discussed not documenting this because there's no action required for users -- the network redirects should be invisible for users.

[pglowacky]

We should do this! This could be a single-line explanation in the playback docs.