* Use `CallRequest` type from rust-web3 crate

* Change CallRequest's `to` field to be optional

Required due to changes in upstream `rust-web3` crate.

* mute warnings from sub2sub module+relay

* cargo fmt --all

* Bump rust-web3 to latest master

* Use tagged release from crates.io

* Add check for `logs_bloom`

Since this is required by the runtime we want to enforce that an
incoming header has this.

Missing two methods right now, which require a `serde::Deserialize`
implemenation before they can be changed.

Let's us avoid using a runtime specific Extrinsic.

* solidity contract

* continue

* upd

* cargo update

* fixes

* ehtereum_headers -> headers

* extracted some common stuff

* ethereum_sync.rs -> sync.rs

* make sync generic

* continue extracting

* continue

* add eth-contract argument

* continue

* some fixes

* contract v2

* continue

* more fixes

* more fixes

* deal with duplicated params

* removed multiple call_rpc variants

* bail_on_error!()

* fn submit_ethereum_transaction

* more fixes

* cargo fmt --all

* fix

* bail_on_arg_error!()

* fix

* fix

* remove async_extra stuff

* start work on finality builtin

remove async_extra stuff

continue

continue

local testnet (Alice + Bob) for node

* added TODO

* substrate-bridge.json -> substrate-bridge-abi.json

* get rid of substrate transactions hashes

* get rid of ethereum transactions hashes

* extracted contract bytecode to separate file

* cargo fmt --all

* avoid duplicate import in contracts

* removed Default::default()

* swapped configurations for sub2eth && eth2sub

* fix compilation

* do not double gas limit when submitting Substrate headers

* fix finality storage

* at least 1 validator required

* shift_session_manager_works

* cargo fmt --all

* solidity contract removed

* consts

* extracted solc compilation details to separate file

* removed (obsolete in future Vec<u8> justification)

* fixed cli option description

* fix typos

* fix grumble

* extracted constants

* log decoded header

* new substrate version + actually verify justification

* intermediate cargo fmt --all

* comments

* disable completion data resubmission

* increased timeouts + _MS -> Duration

* forget completion data after submission

* builtin tests

* headers tests

* cargo fmt --all

* update contract

* Update relays/ethereum/src/ethereum_sync_loop.rs

Co-authored-by: Tomasz Drwięga <[email protected]>

* Update relays/ethereum/src/ethereum_sync_loop.rs

Co-authored-by: Tomasz Drwięga <[email protected]>

* added docs

* OwnedFutureOutput

* more docs fixes

* cargo fmt --all

* encode headers

* consts + docs

* aliases again

* cargo fmt --all

* Update relays/ethereum/src/ethereum_sync_loop.rs

Co-authored-by: Tomasz Drwięga <[email protected]>

* Update relays/ethereum/src/ethereum_sync_loop.rs

Co-authored-by: Tomasz Drwięga <[email protected]>

* Use Duration::from_secs() instead of from_millis()

* grumbles

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* incomplete_headers_are_still_incomplete_after_advance

* add hex-encoded headers to substrate_header_without_signal_parsed

* cargo fmt --all

* Update relays/ethereum/src/sync_loop.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* added comments on Extra and Completion

Co-authored-by: Tomasz Drwięga <[email protected]>
Co-authored-by: Hernando Castano <[email protected]>

This range of commits was mainly trying to integrate the new RPC interface into the existing
codebase, however this turned out to be a little out of scope for the current PR. Instead this work
will be incorporated into a PR which aims to close #72.