New on-chain registration flow (#955)

* Trial of using types and derivation code

* Move new registration code to its own extrinsic

This way we can introduce it without breaking everything just yet

* Use my branch of Synedrion

* Sketch out using the account ID as derivation path

* Basic test setup

* Use a `CountedStorageMap` for `Registered` struct

This lets us use the count as the derivation path for now.

* Add some error handling

* Tidy genesis build

* Add registration struct for new flow

This lets us change the mapping so that instead of being indexed by verifying key we're not indexing
by the signature request account.

* Use updated `RegisteredInfo` struct in tests

* Test flow and validate verifying key

* Encode the signature request account in place

* Update some of the variable names

* Revert registration struct to be indexed by verifying key

The notion of the signature_request_account is meant to be ephemeral, so we don't really need to
have registration know anything about this beyond the initial extrinsic.

* Initialize `RegisteredOnChain` during genesis builds

* Remove check that a `signature_request_account` can only register once

* Insert verifying key into `ModifiableKeys` storage struct

* Remove `dbg!` statement

* Add test to check that a signature request account can register multiple times

* Add benchmark for new registration extrisic

* Add comments around registration flow

* Use `no_std` compatible version of Synedrion

* Use `core` and `alloc` data structures in pallet

* Use remote Synedrion reference

* Make derivation path in benchmarks generic instead of hardcoded

* Use benchmark results for new extrinsic

* Rename extrinsic to `register_on_chain`

* Use `no_std` functions for benches

* Add entry to `CHANGELOG`

* Add a few tests for failure conditions

* Fix breaking changes from #974

* Bump Synedrion to latest `master`

* Add issue number to `TODO` comment

CHANGELOG.md

@@ -19,6 +19,7 @@ At the moment this project **does not** adhere to
 - Jumpstart network ([#918](https://github.com/entropyxyz/entropy-core/pull/918))
 - Add Signer groups and rotation ([#938](https://github.com/entropyxyz/entropy-core/pull/938))
 - Split jumpstart and register flows ([#952](https://github.com/entropyxyz/entropy-core/pull/952))
+- New on-chain registration flow ([#955](https://github.com/entropyxyz/entropy-core/pull/955))
 - Reshare confirmation ([#965](https://github.com/entropyxyz/entropy-core/pull/965))
 - Set inital signers ([#971](https://github.com/entropyxyz/entropy-core/pull/971))
 - Add parent key threshold dynamically ([#974](https://github.com/entropyxyz/entropy-core/pull/974))

pallets/registry/Cargo.toml

@@ -12,9 +12,11 @@ publish   =false
 targets=['x86_64-unknown-linux-gnu']
 
 [dependencies]
+bip32     ={ version="0.5.2", default-features=false, features=["alloc"] }
 codec     ={ package="parity-scale-codec", version="3.6.3", default-features=false, features=["derive"] }
-scale-info={ version="2.11", default-features=false, features=["derive"] }
 log       ={ version="0.4.22", default-features=false }
+scale-info={ version="2.11", default-features=false, features=["derive"] }
+synedrion ={ git="https://github.com/entropyxyz/synedrion/", rev="1d210d149dfeb0dca1dd41d7fac4d0bf03c686fa", default-features=false }
 
 frame-benchmarking={ version="29.0.0", default-features=false, optional=true }
 frame-support     ={ version="29.0.0", default-features=false }