Sapling

This branch adds a dependency that must be installed with make build-deps for it to compile.

⚠ This MR is based on !96 (merged), the 10 first commits are part of !96 (merged), which can be reviewed independently. Comments should be added there.

REVIEW

lib_sapling/

• rustzcash, do not review as susceptible to changes
• core, proceed bottom-up, requires a good understanding of the sapling protocol
• forge, very related to client
• storage, very related to protocol storage
• test/example.ml, useful to review the client and verify_update in the protocol

proto_alpha/lib_protocol/

Storage:

• storage
• sapling_storage, related to lib_sapling/storage.ml
• sapling_services
• contract_services

Michelson:

• script_*

proto_alpha/lib_client_sapling

• wallet
• context
• commands

organization

2 reviewers in the client + lib_sapling/forge

2 reviewers in the protocol + lib_sapling/storage

A more expert review will probably be required for core.ml, so we leave to the reviewers to decide in which depth they want to review it.

Entrypoint for the review: docs/developer/sapling.rst

AFTER/DURING REVIEW

• refactor names that are abbreviations like nf -> nullifier
• split initialization of storage in a separate Migration commit
• Squash everything (don't forget to mention all authors and reviewers in the commit message) and split wrt. protocol/non-protocol
• merge opam-repository first

Sapling umbrella task: nomadic-labs/tezos#65