* Flatten consensus::verify::* to consensus::*
* Move consensus::*::tests into their own files
* Move CheckpointList into its own file
* Move Progress and Target into a types module
QueuedBlock and QueuedBlockList can stay in checkpoint.rs, because
they are tightly coupled to CheckpointVerifier.
* Return Poll::Ready(Err(_)) when verification has finished
* Turn checkpoint::init() into CheckpointVerifier::new()
* Accept IntoIterator<...> for CheckpointVerifier::new()
* Add a CheckpointList type
* Replace the state service with oneshot channels.
* Reject redundant checkpoint blocks
* impl Drop for CheckpointVerifier
* Add fields for caching blocks, and managing verify chains.
* Add current checkpoint functions
* Use a checkpoint range
* Get full backtraces with Err::Try
* Add enums for verification progress and target block heights.
* Replace install_tracing() with zebra_test::init()
* Add a test that mixes good and bad blocks
* Add timeouts to the checkpoint test futures
* Use spandoc correctly
* Refactor consensus test error handling
* Delete a checkpoint test that will soon be obsolete
* Only initialise tracing once for the block tests
* Use tracing in the checkpoint tests
* Move BlockVerifier and tests into block.rs
* Update a BlockVerifier comment
* Tweak some TODO comments
consensus: Add a checkpoint verifier stub
This stub only verifies blocks whose hashes are in the checkpoint
list.
It doesn't have tests, chain child verifies to their ancestors, or
support checkpoint maximum height queries.
Part of #429.