* initialize the work on parsing orchard data in V5
* add the rest of orchard serialization
* fix serialization according to spec
* fix arbitrary for Signature<SpendAuth>
* move deserialization of AuthorizedAction to shielded_data module
* use `from_bits_truncate` to generate valid arbitrary flags
* change panic message
* fix serialization/deserialization when nActionsOrchard is empty
* fix Halo2Proof deserialization
* implement ZcashSerialize and ZcashDeserialize for flags
* implement ZcashSerialize and ZcashDeserialize for orchard::tree::Root
* use ZcashSerialize and ZcashDeserialize for binding_sig
* implement from_parts()
* implement Arbitrary for Signature<Binding>
* add trusted preallocate with tests
* fix Arbitrary for orchard Nullifier
* Use zcash_serialize_bytes instead of write_compactsize
Co-authored-by: teor <teor@riseup.net>
* Add functions for serializing and deserializing split arrays
In Transaction::V5, Zcash splits some types into multiple arrays, with a
single prefix count before the first array.
Add utility functions for serializing and deserializing the subsequent
arrays, with a paramater for the original array's length.
* Use zcash_deserialize_bytes_external_count in zebra-network
* Move some preallocate proptests to their own file
And fix the test module structure so it is consistent with the rest of
zebra-chain.
* Add a convenience alias zcash_serialize_external_count
* Explain why u64::MAX items will never be reached
teor
Alfredo Garcia