NIFI-7498 Adding unique prefix to every swagger operationId

[EndzeitBegins]

Description of PR

Adds a prefix consisting of package and class name to every operationId to ensure it is unique.
The problem this fixes is desribed in NIFI-7498.

The prefix can be excluded in the method name when generating a client by using the flag --remove-operation-id-prefix (both openapi-generator and swagger-codegen).

For all changes:

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[github-actions]

We're marking this PR as stale due to lack of updates in the past few months. If after another couple of weeks the stale label has not been removed this PR will be closed. This stale marker and eventual auto close does not indicate a judgement of the PR just lack of reviewer bandwidth and helps us keep the PR queue more manageable. If you would like this PR re-opened you can do so and a committer can remove the stale tag. Or you can open a new PR. Try to help review other PRs to increase PR review bandwidth which in turn helps yours.