Restore service must rely on crypt plugin name instead of key holder name

[aafemt]

Currently database is restored as encrypted only if both crypt plugin name and key holder name are provided in command line or service parameters. Providing crypt plugin name should be enough because key holder may be configured globally in firebird.conf, for particular database in databases.conf or not needed for the crypt plugin at all.

[AlexPeshkoff]

Should same logic be applied to backup of encrypted database?

[aafemt]

Backup part is described in #7943.