Turbopack: Add a custom serde_self_describing Serializer/Deserializer (#86885)
Implements a minimal custom serde `Serializer` and `Deserializer` on top of bincode with a custom self-describing format. The API is exposed as functions that can be used in `#[bincode(with = "...")]` attributes.
This doesn't encode as efficiently as `pot`, but it lets us get rid of that dependency entirely. It also gives us a more efficient option than `serde_json` for certain values.