improve the _atomic_ benchmark plots (dragoon/komodo!79)

this MR improves the "_atomic_" script in `benches/README.md` to allow filtering _species_ to show in the _multibar_ plot.

in addition to this, the warmup time and the number of samples of Criterion have been increased back to 3sec and 100 respectively.

> **Note**  
> the benchmarks take 15min on my machine, i.e. by running the following two commands in Nushell
> ```bash
> cargo criterion --output-format verbose --message-format json --bench field_operations out> field.ndjson
> cargo criterion --output-format verbose --message-format json --bench curve_group_operations out> curve.ndjson
> ```

## results
![foo](/uploads/5cdc5af344f4ad0510b3d1993c09389f/foo.png)
![bar](/uploads/2563b465727d85b886f77c5574ae616d/bar.png)
![baz](/uploads/7a485c61d218c8e065afdd880171a12b/baz.png)