Re #8573 - Added some CertificateService tests and improved CryptographyService tests of methods that extract public keys
Re #8573 - Improved testing of extract_public_key_from_certificate and extract_public_key_from_private_key methods
Re #8573 - Implemented extract_public_key_from_certificate
Re #8573 - Changed extract_public_key method in such way that it now extracts a public key from a private key instead of a certificate
Re #8472 - Improved SQL connection/cursor fixtures in such way that connection to DB happens only once per test module