* 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]>

* fix delivery transaction estimation in greedy relayer

* fixed typo

* improve logging

* improve logging

* fmt

* fix compilation

* fmt

* Update relays/lib-substrate-relay/src/messages_target.rs

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

* review

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

* fix(spellcheck): test of fixing

* fix(hunspell): improved many typos etc.

* fix(hunspell): all errors solved

* fix(hunspell): extended scope of files - the build should fail

* Return error code.

* Fix spelling, sort dictionary.

* fix(hunspell): added fix to gitlabs check

* fix(typo): one typo and test of verification on github

* fix(typo): one typo

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

* cli option for greedy relayer + run no-losses relayer by default

* trigger build

* Revert "trigger build"

This reverts commit f77ae3a6.

* NoLosses -> Rational

* use real conversion rate in greedy relayer strategy

* only accept positive, normal numbers in FloatJsonValueMetric

* shared conversion rate metric value

* clippy

greedy relayer don't need message dispatch to be prepaid if dispatch is supposed to be paid at the target chain (#1016)

* use plain source_queue view when selecting nonces for delivery

* Revert "use plain source_queue view when selecting nonces for delivery"

This reverts commit f1fdc3fa.

* Revert "Revert "use plain source_queue view when selecting nonces for delivery""

This reverts commit ccefa5ec.

* clippy

* fmt

* introduce relayer mode enum

* removed MaximalReward mode

* TODO

* Saturating -> SaturatingAdd

* ref issue in TODOs

* Update relays/messages/src/message_race_delivery.rs

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

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

* CI: do not trust this CI 1

* CI: don't want to trigger unneded statuses

* CI: debug 1

* CI: new CI

* CI: temp allow failure

* CI: exclude paths

* doc: check if docs won't trigger pipelines

* doc: check hybrid changes pipeline

* doc: do not push excluded files together with others

* CI: undebug fmt

* CI: better deny

* CI: fix deny and spellcheck

* CI: global backtrace

* CI: deny config

* CI: publishing

* Dockerfile: metadata fix [skip ci]

* CI: revert me

* CI: debug bash

* CI: mv ci.Dockerfile; fix buildah bug

* CI: fix artifact name

* Dockerfile: fix context

* CI: separate deny check licenses

* CI: when to run

* CI: unneded stuff in these Dockerfiles

* CI: merged test-refs and build-refs

* CI: test-build optimizations

* CI: changes, web, scheduled pipelines now work as intended

* CI: use tested production CI image

* CI: substitute GHA

* Fix clippy.

* Moar clippy fixes.
...

* require lane source -> target headers when weknow all headers that have produced messages, but are unable to deliver all messages because of unrewarded relayers vec capacity

* Update relays/messages/src/message_race_delivery.rs

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

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

* 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

* Update copyright date to 2021

* Bump date in license header template

* on-demand headers relay

* bool::then

* move file

* atomic submit_signed_extrinsic

* remove cli options from future

* test on-demand relay

* TODOs

* fixed initialization call for Westend -> Millau

* Update relays/client-substrate/src/client.rs

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

* removed on_demand_headers_relay.rs

* on_demand_headers_relay traces

* fix compilation

* fmt

* docs

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

* 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.