Rubin DP docs: recommend `/deleted-sundays` for tmp and outputs

[hombit]

We should recommend RSP users to use /delete-sundays/${USER} for large outputs and for Dask temporary data. We can start with
https://docs.lsdb.io/en/latest/tutorials/pre_executed/rubin_dp1.html
https://docs.lsdb.io/en/latest/tutorials/pre_executed/dp1-gaia-epoch-prop.html

[nevencaplar]

Incorporate the following information that Observatory has shared:

/scratch is now /deleted-sundays: The /deleted-sundays directory in the Notebook Aspect is writeable by all, and has no quota, but is cleared out on Sundays. This directory is temporary storage for large intermediate files (e.g., byproducts of data processing).