* fix on-different-forks metrics during initialization

* "initialize" parachain finality pallet in on-demand parachains relay

* decrease converstion rate requests count

* more error logging

* fix compilation

* clippy

* verify that GRANDPA pallet is not initialized before submitting initialization transaction

* spelling

* 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