Migration Needed: Character system.favorites is now official; migrate Tidy favorites to the real thing

[kgar]

A migration is needed to move Tidy favorites to the system.favorites field on character actors. For migrations relevant to 3.0.x, promote the migrations UI to using an accordion, with the latest migrations at the top and the rest is descending order by version.

This migration should be optionally invokable from the Migrations menu, whether to all character sheets or to an individual one by UUID.

Notify the GM of this available migration in chat, and allow them click a button to not show this again.

Use a generic header message for available migrations, and then use localizable bullets or list items to denote what migrations are available. The button to not show again should have its own localization. This is so, in the future, at least some of the message will always be localized.