* Unify error enums in substrate and ethereum clients with `thiserror`

Related to https://github.com/paritytech/parity-bridges-common/issues/857

* Add license pre-amble

* rustfmt

* Fix spelling

* Alter gitlab.

* Use substrate's rustfmt.toml

* cargo +nightly fmt --all

* Fix spellcheck.

* cargo +nightly fmt --all

* format.

* Fix spellcheck and fmt

* fmt?

* Fix spellcheck

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

* I'm just trying to do my job

* spelling

* read justifications from stream using channel + task that fills that channel

* Arc<Mutex> -> Mutex

* shared conversion rate metric value

* clippy

* always run on-demand headers relay in complex relay

* fix compilation

* do not spawn additional task for on-demand relays

* compilation

* prefix in relay loops logs

* fmt

* complex headers+messages relay

* post-merge fix

* fix + test issue with on-demand not starting

* administrative metrics

* fmt

* fix compilation

* fix compilation again

* and another one

* remove GenericLoopMetrics

* chttp -> isahc

* remove redundant marker

* not about price metrics

* fmt

* slightly changed relay loop initialization

* git mv

* clippy

* more clippy

* loop_run -> run_loop

* review and clippy

* clippy

* Remove chains.

* Move relay clients.

* Flatten generic.

* Fix fmt.

* Nest some crates.

* Alter command execution to make it easier to add new bridges.

* Rename sub-dirs.

* cargo fmt --all

* Address clippy.

* Update relays/substrate/src/rialto_millau/cli.rs

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

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

* more tests for finality relay

* clippy

* remove env_logger dep

* fmt

* more clippy

* removed prune_unjustified_headers

* review

* finality proofs relay

* SyncHeader::is_mandatory

* empty ancestry proof

* logs

* fixed submit condition

* fixed wrong split index

* tick comment

* recent_finality_proofs

* basic finality loop tests

* removed obsolete files

* rename files in substrate relay

* fmt

* clippy

* fixed TODOs

* clippy

* stop syncing if target node is out of sync

* more clippy

* more clippy

* Update relays/finality-relay/src/finality_loop.rs

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

* Update relays/finality-relay/src/finality_loop.rs

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

* Update relays/finality-relay/src/finality_loop.rs

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

* docs

* moved doc

* typo

* Update relays/finality-relay/src/finality_loop_tests.rs

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

* Update relays/finality-relay/src/finality_loop_tests.rs

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

* header_and_finality_proof_by_number -> header_and_finality_proof

* VecDeque isn't required (because of make_contiguous)

* fixed wrong expect

* Update relays/finality-relay/src/finality_loop.rs

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

* Update relays/substrate/src/rialto_headers_to_millau.rs

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

* Update relays/substrate/src/rialto_headers_to_millau.rs

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

* RialtoSyncHeader

* Update relays/finality-relay/src/finality_loop.rs

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

* Update relays/finality-relay/src/finality_loop.rs

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

* removed wrong comment

* Update relays/finality-relay/src/finality_loop.rs

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

* fix used runtime methods names

* fix for new jsonrpsee

* fix comment

* initialize finality verifier pallet

* fmt

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