issue #1060 pgp decrypt method that mimics error behavior

[IvanPizhenko]

This PR introduces 100% jvm based method for the decryption.

close #1060

Tests (delete all except exactly one):

• Tests added or updated

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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

[tomholub]

Thank you - this is what I needed, but needs some improvements. I didn't look at the tests yet (will later).

It seems FORMAT error are not handled? For example, what will happen if I enter "abcd".toByteArray() as the data? It seems like it would throw "OTHER / wrong key" which is not correct.

[DenBond7]

Leaved a few comments. Please look at them.

[IvanPizhenko]

@tomholub @DenBond7 made some fixes here, please review

[DenBond7]

Thank you. Looks good. Approved

[DenBond7]

@tomholub Please review it. I will merge it after your approving

[tomholub]

Looks good, with tiny changes, from my end it's good to merge it. I'll let Den do the final review and merging. Thank you!

Changed the approving status. I'll approve it after Tom. Due to difficulty of the current issue(decryption process).

[tomholub]

Ok Den, after the above changes, I'll do my approving review, then you can do yours.

[IvanPizhenko]

@tomholub @DenBond7 I've made some more fixes according to Tom's comments, so please check them

[tomholub]

Thank you! Looks good to me. Will let Den take another look and merge it.