Introduce a docker image that matches Hyperscale (Citus)

[marcocitus]

With https://github.com/citusdata/citus/pull/4434 our docker images will automatically become a lot more useful for testing and trying out Citus, since you can immediately use Citus functionality such as columnar storage and distributed tables in a single container without having to add worker nodes.

Our current docker images are very minimalistic, which makes them a useful building block, but for testing and trying out Citus it would be nice if we had a more complete version that matched Hyperscale (Citus) in terms of extensions (e.g. PostGIS, HLL, pg_cron).