Remove path prefix from filename in profile

Currently in profiles we include the full filename in the profile information. These filenames look like this:

/srv/conda/evs/notebook/libs/python3.8/site-packages/fsspec/asyn.py

We might consider chopping off everything before site-packages so that we have the following:

fsspec/asyn.py

The path prefix is useful in that it helps us to immediately identify a file if we're on the same machine, but it also leaks slightly personal information, and is generally not helpful especially if we're looking at these results on a different system. Aesthetically this is also often the longest part of the printed result, and results in wonky display issues.

I propose that we strip out everything up-to-and-including "site-packages"

([example performance report for reference](https://gistcdn.githack.com/stb2145/2066b975a1fcb00b251269d51e4bde73/raw/261359fb8df04dd240be9f4fa2a7b9997fa71229/theta_dist_with_dims-dask-report.html))