Create 2023 Q4 roadmap (#7551)

* Add placeholder for 2023 Q4 roadmap

* Update docs/source/contributor-guide/quarterly_roadmap.md

Co-authored-by: Andrew Lamb <[email protected]>

* Apply suggestions from code review

Co-authored-by: Andrew Lamb <[email protected]>

* Add proper links to issues

* Fix bad issue link

* Update docs/source/contributor-guide/quarterly_roadmap.md

---------

Co-authored-by: Grayden Shand <[email protected]>
Co-authored-by: Andrew Lamb <[email protected]>

Author: 3 people

docs/source/contributor-guide/quarterly_roadmap.md

@@ -21,6 +21,12 @@
 
 A quarterly roadmap will be published to give the DataFusion community visibility into the priorities of the projects contributors. This roadmap is not binding.
 
+## 2023 Q4
+
+- Improve data output (`COPY`, `INSERT` and DataFrame) output capability [#6569](https://github.com/apache/arrow-datafusion/issues/6569)
+- Implementation of `ARRAY` types and related functions [#6980](https://github.com/apache/arrow-datafusion/issues/6980)
+- Write an industrial paper about DataFusion for SIGMOD [#6782](https://github.com/apache/arrow-datafusion/issues/6782)
+
 ## 2022 Q2
 
 ### DataFusion Core