Re #8472 - Changed delete methods in repositories in such way that delete methods now return True only when at least one row was deleted
Re #8472 - Fixed a bug in PrivateKeyRepository that resulted in inability to get a single private key from the repository
Re #8471 - Merge implement DAO - source code
Re #8471 - Implemented selection of all private keys
Re #8471 - Error correction after review
Re #8471 - Simplification of CRUD functions- conversion source of private key repository to one file- added comments
Re #8471 - Modified source- deleted redundat files- deleted '_impl' from repositories filename