Draft: Abstract binary serialization behind a ReaderT newtype with pure encode/decode interface

The current Binary implementation unnecessarily exposes an exclusively IO interface, preventing a pure encode/decode.

Motivation: #17363

This patch replaces the current IO serialization API with Put/Get readers, and additionally implements a Generics default instance for the updated Binary class.

This refactoring opens up:

• Pure encode/decode
• Abstracting the copy-paste duplication between ghc.BinIface.{readBinIface, writeBinIface}, ghc.HieBin.{readHieFile, writeHieFile}, and haddock.Haddock.InterfaceFile.{readInterfaceFile, writeInterfaceFile}
• Replacing the GHC-specific implementation with one of the standard libraries (#3379) now that the types align more closely with reader-like implementations.