Document using Yoast Premium's redirects instead of ours

[jazzsequence]

If a Yoast license key exists, users can use Yoast SEO redirects instead of our own. We should document this.

Acceptance Criteria:

• Document disabling Altis redirects in favour of Yoast's redirects

[jazzsequence]

This also requires that we actually have a copy of the premium plugin to test this (which I do not).

[roborourke]

You can grab credentials and composer set up from one of our internal private project repos or alternatively I think the creds should should be in 1pass. Ping me in Slack if you need a pointer.

I think rather than checking for a license key (there are few ways that could be provided I think) I believe the plugin itself has some helper function last I checked, like is_premium() or something. Or you could check for the existence of the Yoast redirect code directly.

Given this is specific to Yoast premium a subcommand of wp altis migrate like you suggest would make sense. Would need to look into how Yoast SEO stores and handles redirects to know exactly how to do this.

I'd probably mark this as a could have as both could exist side by side without any problem.