[docs] Update or Remove Quarterly Roadmap Documentation

[graydenshand]

The Quarterly Roadmap is intended to "give the DataFusion community visibility into the priorities of the projects contributors". However, the most recent entry is for Q2 2022.

This documentation should either be updated to reflect current priorities (e.g. for Q4 2023), or removed.

Happy to help out with this if I can!

[alamb]

Thank you @graydenshand -- that would be super helpful to update this documentation

The major items I know of that are currently ongoing are:

1. @devinjdangelo is cranking along with improving write / output capabulity [DataFrame] Parallel Write out of dataframe  #7079
2. @jayzhan211 and @izveigor are leading the charge for adding support for array

There is also writing of a paper #6782

In the past I have found a good way to get a community roadmap is to create a skeleton PR with some ideas and then we'll solict help from others to add what they are thinking of / planning on working on

I can help with circulating the content around to others

[yjshen]

I have been occupied with preparing a company internal product for launch recently and almost finished. My next goal is to develop a stand-alone AP engine service using DataFusion and FlightSQL. (And use it internally as an alternative to Spark for small OLAP queries for both cost and performance efficiency). I have seen some impressive implementations inside InfluxDB and Greptime, and I would like to know if this project (datafusion-jdbc maybe?) has a broader interest.

[alamb]

I think an example / reference implementation of FlightSQL in rust would be helpful for many reasons including helping find missing parts of the API as well as promoting / making DataFusion more compelling across a wider set of usecases