[REQ] First-time contributor labeling and core team tagging

Is your feature request related to a problem? Please describe.

Some technical committees have slow response times, which could potentially be off-putting to new contributors. I think it would be helpful to have a core team member in the loop on all first-time contributors.

Describe the solution you'd like

If possible, label pull requests from first-time contributors as such and assign @OpenAPITools/openapi-generator-core-team as reviewer or assignee.

Describe alternatives you've considered

Rather than relying solely on technical committees, maybe we could have a "community" group of contributors who regularly respond to a variety of pull requests. Perhaps as a subset of members of the collaborators group (@macjohnny and @ybelenko are examples of folks who I've seen do it)

Additional context

See #6806 for an example of a new contributor who had pinged 5 times over 3 weeks without response. Additionally, we may want to consider explaining our pull request process because it may not be obvious to contributors that pinging multiple times in a short period could be counter-productive to getting a response.

Start by reviewing the example in #6806 and the repository's pull request process, both named in the issue. Define whether the desired outcome is first-time-contributor labeling, core-team assignment, community coverage, contributor guidance, or a combination; done requires an agreed scope and documented behavior.