add ARE instructions to README

[aekiss]

The "getting started" section of the README is a bit out of date and could do with instructions on using ARE

[aekiss]

eg https://forum.access-hive.org.au/t/introduction-to-cosima-cookbook-data-explorer-and-access-nri-intake-catalog/1144#start-are-jupyterlab-session-8

[angus-g]

Also related: #322

[aekiss]

Also see https://github.com/aekiss/HPC-Data-CFD-2023/blob/main/README.md#start-are-jupyterlab-session