Refactored EncryptorDecryptor handling

[bendk]

Don't pass EncryptorDecryptor to database functions, this is redundant because the DB has it's own encdec.

This is the initial code from #7343 that I think is still useful. I didn't keep the change that made EncryptedLogin::decrypt input a LoginsDb, since as @jo pointed out that function isn't expected to make changes to the database.

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