* Add test for invalid set id.

* cargo fmt --all

* Update modules/finality-verifier/src/lib.rs

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

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

* Add method for unchecked header imports

* Update docs for importing unchecked headers

* Import unchecked headers in HeaderChain implementation

* Fix Clippy warnings

* Move unchecked header import out of Verifier struct

* Clean up unchecked import tests

* Change HeaderChain API to accept iterator of headers

* Use chains of headers in tests

* Remove unused Result return type when appending finalized headers

* Add test which shows that genesis changes are not enacted

* Use initial header's hash for unchecked authority set changes

* Appease Clippy

* Check ancestry before making unchecked writes

* Fix typo

* Fix Clippy warning

* Add note about `ancestry_proof` structure

* Use best hash storage item directly

Co-authored-by: Svyatoslav Nikolsky <[email protected]>

* Get pallet compiling with FRAME v2

* Get tests compiling

* Stop printing metadata in tests

* Remove more metadata related code

* Remove unecessary storage attribute

* Add skeleton for `pallet-finality-verifier`

* Sketch out implementation for importing finality proofs

* Get pallet compiling

* Introduce skeleton for mock runtime

* Start using real Grandpa types in finality pallet

* Redefine types in header chain primitives crate

* Implement HeaderChain for Substrate bridge pallet

* Plug Substrate Bridge Pallet into verifier mock

* Fix compilation of `header-chain` primitives

* Start writing to base pallet storage

* Add first "cross-pallet" test

* Move keyring primitives used in tests to shared crate

* Stop pulling `std` deps into `no_std` builds

* Revert "Stop pulling `std` deps into `no_std` builds"

This reverts commit f74dd660.

* Revert "Move keyring primitives used in tests to shared crate"

This reverts commit b774fa73.

* Use new SS58Prefix type in mock

* Start using `bp-test-utils` in finality pallet

* Start using real justification code

* Get a test working with real justification verification

* Add basic tests for invalid proofs

* Get rid of AncestryProof config type

* Add error types to transaction outcome

* Bound number of headers allowed in a single ancestry proof

* Disallow invalid authority sets

* Remove unused items

* Add some documentation

* Get rid of Clippy warnings

* Rename BaseHeaderChain to TransactionVerifier

* Remove unused code

* Make dummy trait implementations more generic

* Fix more Clippy complaints

* Update tests to use fix for duplicate headers

* Fix benchmarking compilation

* Rename TransactionVerifier to InclusionProofVerifier