Re #8471 - Edited Certificate object- due to database modification
Re #8471 - Edited constants
Re #8471 - Corrected stylistics and warnings
Re #8471 - Implemented DB communication- Implementation of communication with specific tables (Certificate, PrivateKey)
Re #8471 - Edited arguments in headers of functions
Re #8471 - Created constants of DB names- Constant for each of names in DB (table, column)
Re #8471 - Implemented DB communication- implemented operations create, read, update, delete- created file with constants contains name of DB file and default values in DB
Re #8471 - Initialization of DAO implementation- created data class according to DB tables (Certificate, PrivateKey)- created abstract class for DB communication