MINIFICPP-2717 Remove old docker testing framework

[lordgamez]

https://issues.apache.org/jira/browse/MINIFICPP-2717

Depends on #2101

Ran verify-package jobs with FIPS https://github.com/lordgamez/nifi-minifi-cpp/actions/runs/22097249495 and without FIPS https://github.com/lordgamez/nifi-minifi-cpp/actions/runs/22096163753 - seems to be working, although there is a flaky test scenario in the repository.feature suite that needs to be investigated separately

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