MINIFICPP-2294 Flow migration

[martinzink]

-Removed deprecated "Send Body" and "Disable Peer Verification" properties from InvokeHTTP
-Removed deprecated "Message Key Field" property from PublishKafka
-Removed deprecated SSL related properties from PublishKafka and replaced them with a generated SSLContextService

Thank you for submitting a contribution to Apache NiFi - MiNiFi C++.

In order to streamline the review of the contribution we ask you
to ensure the following steps have been taken:

For all changes:

• Is there a JIRA ticket associated with this PR? Is it referenced
  in the commit message?

• Does your PR title start with MINIFICPP-XXXX where XXXX is the JIRA number you are trying to resolve? Pay particular attention to the hyphen "-" character.

• Has your PR been rebased against the latest commit within the target branch (typically main)?

• Is your initial contribution a single, squashed commit?

For code changes:

• If adding new dependencies to the code, are these dependencies licensed in a way that is compatible for inclusion under ASF 2.0?
• If applicable, have you updated the LICENSE file?
• If applicable, have you updated the NOTICE file?

For documentation related changes:

• Have you ensured that format looks appropriate for the output in which it is rendered?

Note:

Please ensure that once the PR is submitted, you check GitHub Actions CI results for build issues and submit an update to your PR as soon as possible.

[szaszm]

I would close this until we figure out how to do it in a C2-friendly way

[szaszm]

my mistake, I misunderstood parts of the PR. Apparently migrations are unversioned, idempotent, so they run on all input flow definitions, regardless of whether that was meant to target older or newer minifi versions. This way it's not a problem if we don't know what minifi version is targeted by the C2 server.

I'm still not sure if an unversioned approach is the right one, but it's not inherently bad, like I thought an hour ago.