Add separate compression layer to Pheix::Model::Database::Blockchain

LZW::Revolunet compression API are hardcoded in Pheix::Model::Database::Blockchain.

In case of transition to https://gitlab.com/pheix-research/bzip2 we should remove all LZW::Revolunet and add Compress::Bzip2. This is not scalable and efficient approach.

If we add smth like Pheix::Model::Database::Blockchain::Compression with generic API and move all compression dependent logic there, it will be much better;