Implemented all types for ChonkyBFT. Work on this is all on the roles
crate. Tests in roles crate are passing. Note that I'm not keeping the
old types, that's because `ReplicaCommit` has no changes to it (I
checked and serialization is the same for old and new, old signatures
still work) as well as `CommitQC` and `FinalBlock`. Any type that an EN
could receive, or that ends on our database, doesn't suffer any
alterations. So it seems that the upgrade to ChonkyBFT is
backwards-compatible for ENs. Since we only have one validator, we can
upgrade the whole network without a planned hard fork.

Part of BFT-452

- Everything in chonky_bft folder is basically new.
- UTHarness was moved to chonky_bft/testonly.rs. Several changes to it
though.
- All tests that use UTHarness were moved to chonky_bft/tests. Some of
the old unit tests were repurposed, but a fair amount of the tests in
chonky_bft/tests are new.
- The tests in tests.rs were split between tests/mod.rs and
tests/twins.rs (except for a few that used UTHarness and were moved as
said before). There were no changes to them though.

Part of BFT-452