* Move blockchain::rocksdb into a separate crate

* Add license and description for blockchain-rocksdb

* Rename .0 -> .backend for easier extension

* Refactor set_genesis to a separate function

* Write to database in batch

* Make db opening return error

* Remove all unwrap in rocksdb backend layer

* Reliable open_or_create for rocksdb

* Update test vectors to v0.7.1 and integrate CI

* Remove transfer workaround

* Remove unnecessary mut

* [WIP] Initial runover of the 0.7 spec

* Make beacon compile again

* Add missing docs

* Fix block authoring logic

* Fix issue when attestation processing failed, state is changed

* Pass all tests for 0.7

* Update version tag

* Add support for voluntary exit tests