ARROW-9837: [Rust][DataFusion] Added provider for variable

[wqc200]

Select @@Version;

@@Version is a variable, and if we want to get its value, we should get it from outside the system.

[github-actions]

Thanks for opening a pull request!

Could you open an issue for this pull request on JIRA?
https://issues.apache.org/jira/browse/ARROW

Then could you also rename pull request title in the following format?

ARROW-${JIRA_ID}: [${COMPONENT}] ${SUMMARY}

See also:

• Other pull requests
• Contribution Guidelines - How to contribute patches