[ref] bc-db-reader: rearrangement by storage type (blocks, indexes)

lib/modules-lib/bc-db-reader/src/blocks.rs

lib/modules-lib/bc-db-reader/src/blocks/fork_tree.rs

lib/modules-lib/bc-db-reader/src/currency_params.rs

lib/modules-lib/bc-db-reader/src/current_meta_datas.rs

lib/modules-lib/bc-db-reader/src/entities/block.rs

...dules-lib/bc-db-reader/src/entities/current_meta_datas.rs

lib/modules-lib/bc-db-reader/src/entities/identity.rs

lib/modules-lib/bc-db-reader/src/filters/identities.rs

lib/modules-lib/bc-db-reader/src/indexes.rs

lib/modules-lib/bc-db-reader/src/indexes/balance.rs

lib/modules-lib/bc-db-reader/src/indexes/certs.rs

lib/modules-lib/bc-db-reader/src/indexes/identities.rs

lib/modules-lib/bc-db-reader/src/indexes/sources.rs

lib/modules-lib/bc-db-reader/src/lib.rs

lib/modules-lib/bc-db-reader/src/paging.rs

lib/modules-lib/bc-db-reader/src/readers.rs

lib/modules-lib/bc-db-reader/src/tools.rs

lib/modules/blockchain/bc-db-writer/src/lib.rs

lib/modules/blockchain/bc-db-writer/src/writers/block.rs

...ules/blockchain/bc-db-writer/src/writers/certification.rs