feat!: overhaul animation configuration

[j-hui]

This is still a work in progress and needs more thought.

Goals of this overhaul are:

• Make configuration concise, explicit, and extensible
• Get rid of ambiguity warts like { "dots" } vs "dots" and { my_pat } vs { pattern = my_pat }
• Introduce a default BAD pattern that is shown when patterns are misconfigured
• Make it easier to inspect, debug, and compose animations

At the moment, animations are just a mess of types. Maybe it's time to introduce a proper Anime class/interface with methods and everything.

When this lands I will release it as part of V2.

Closes #161