Allow customization of the temporary directory for `dvc exp --queue`

Hi team 👋

Thanks for the wonderful tool!

I am exploring a use-case for DVC along with other tools which I rely upon in my projects and was wondering whether there's a way to customize the temporary directory for the experiments queue mechanism.

I have tried adding the --temp command but the results seems to be the same and each experiment still runs in a separate environment which downloads the large genomic files into each of those experiments.

$ dvc exp run -S "annotation_tool=dfast,prokka" -S "outdir=results" --queue [[--temp]]

The feature request here is the (optional) ability to run the experiments in the same directory as opposed to individual directories (sensible default).

Happy to provide other details if needed.

Start at the dvc exp run --queue entry point and trace how the experiment queue creates separate temporary environments. Reproduce the genomic-file download behavior with the command shown in the issue, then determine where an optional shared temporary-directory setting belongs. Done means queued experiments can use the same directory when requested while retaining separate directories by default.