Re #8476 - Auxiliary script for database initialization, FileAnchor
Re #8476 - Clarity update.
Re #8476 - Changed the name of `CertificatesUsages` to `CertificateUsages`.
Re: #8471 - Modified database- password can be null- FKs in CertificateUsages can not be null
Re #8471 - Modified scripts and database- relation between Certificates and CertificateUsages tables on delete 'no action' >> 'cascade'
Re #8471 - Tested direct DB communication- implemented tests for Certificates and PrivateKeys tables via DBManager
Re #8471 - Created database file