* Introduce new mocking proc to replace:
- makeFakeValidatorPrivKey
- hackPrivKey
- getNextBeaconProposerIndex
- addBlock
- makeBlock
* Add comments on datastructure unsynced with the spec
* Add merkle tree constructor and initial mocking for deposits (missing merkle proofs)
* [Mock] Implement sparse merkle tree and merkle proof builder
* [Mocking] Genesis deposits
* Add compact_committees_roots init + mock genesis state
* [Tests] Add first deposit test using the new mocking procedures
* [Tests -deposits] add at and over 32 ETH deposit tests
* [Tests - deposits] Add test for validator top-up
* [Tests -deposits] Mention the TODO to test for invalid conditions
* [Tests] Add stub to test "is_valid_genesis_state"
* [Merkle proofs] Implement round-trip checks
* Deactivate roundtrips test
* SSZ - use EF convention for hash_tree_root / hashTreeRoot
* [Tests - Attestation] Attestation mocking + initial test
* Add mocking + 3 new tests for valid attestations + mention future invalid attestation tests
* Add crosslinks test (1 failing to attestations in block being duplicated in state transition)
* Single attestation crosslink test - workaround https://github.com/status-im/nim-beacon-chain/issues/361
* Add test for failed crosslink penalty
* Rebase fixes + add refactored tests to test suite
* justif-finalization helpers first batch
* Add 234 finalization tests
* Fix justif test, Rule I 234 finalization does not happen with sufficient support.
(Also unittest check template does not fail properly in some cases)
* Add tests for all finalization rules
* Properly delete nim-byteutils following c91727e7e5 (diff-7c3613dba5171cb6027c67835dd3b9d4)
* use digest helper for deposit root
ca4f29caca