NIFI-3024 - Encrypt-toolkit flow.xml.gz support

[brosander]

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[alopresto]

@brosander and I discussed this today and there are a couple small edge cases outstanding. As he will be away from his computer for a few days, I am taking over and will have an updated PR (may need to open a new one as I cannot push to his branch) tomorrow. Will update/close here and link to the new one then.

[olegz]

@brosander not sure if you noticed there is a merge conflict that needs to be addressed

[YolandaMDavis]

@olegz I think @alopresto is taking over this PR and may create a new one, per his comment

[alopresto]

I have created PR 1261 to implement this. Recommend this PR be closed.

[brosander]

closing in favor of #1261