distill `rc-zip` down to fundamental types

[CosmicHorrorDev]

rc-zip contains the fundamental types for doing ~anything with the rc-zip-* crates, but it also contains a lot of additional complexity from the perspective of e.g. an rc-zip-{sync,tokio} consumer. i think it'd be much easier to keep the public API stable if all of the parser/fsm specific stuff was moved to some other crate (rc-zip-winnow maybe?) that can be kept as an internal implementation detail of rc-zip-{sync,tokio}