Make some issues be *classified* as good for newcomers

I have found out at https://opensource.guide/how-to-contribute/#finding-a-project-to-contribute-to that:

> If you’re looking for existing issues you can fix, every open source project has a /contribute page that highlights beginner-friendly issues you can start out with. Navigate to the main page of the repository on GitHub, and add /contribute at the end of the URL

AskQL is not different and it has https://github.com/xFAANG/askql/contribute , however this page is... empty and saying:

> **This repo doesn't have any good first issues, yet**
> Once its maintainers label issues and pull requests for new contributors, they will begin to appear here.
> In the meantime, you can look at all of the issues in this repository.

Surprisingly, it [turned out](https://docs.github.com/en/github/building-a-strong-community/encouraging-helpful-contributions-to-your-project-with-labels) that marking issues as "good first issue" is **not** enough for the issue to appear there, it just increases the likelihood.

To compare, [React's /contribute page](https://github.com/facebook/react/contribute) shows **tons** of issues, most of which are even not marked as "good first issue".

It would be great to figure out what we should do to make our list non-empty.

Review the repository's open issues and the GitHub /contribute and label guidance linked in the report. Define a consistent way to identify and classify suitable newcomer issues so they appear on the repository's /contribute page; no files or tests are named, so completion requires deciding the process.

Written by the indexing model from the issue text.