[code ok] issue 441 remove passphrase table

[sosnovsky]

This PR removes PassPhraseObject model and adds optional passphrase field to KeyInfo class.

close #441

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Tests:

• Tests added or updated - I removed tests for methods which are not used anymore, and also added check for passphrase in testKeyInfoInit test

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To be filled by reviewers

I have reviewed that this PR... (tick whichever items you personally focused on during this review):

• addresses the issue it closes (if any)
• code is readable and understandable
• is accompanied with tests, or tests are not needed
• is free of vulnerabilities
• is documented clearly and usefully, or doesn't need documentation

[tomholub]

Still need to go through the rest of the code (checked about half) but it's looking good. Left some comments.

[tomholub]

Other than earlier comment about forgetting pass phrases on logout, the code looks good. Will now do manual testing.

[tomholub]

Looks good, waiting for updated xcode to try