Clean up profiling features

[thpani]

I'm at a loss about our profiling features:

• running.md tells me to use --profiling to write profile-rules.txt and points me to check profiling.md.

• profiling.md however, does not even mention --profiling. Instead, it tells me to use --smtprof to produce profile.csv and visualize it using script/heatmap.py. --smtprof is not documented in running.md, aside from saying that it is incompatible with --profiling=false.

• On top, we have script/prof.py, which is still on Python 2 and digests log.smt. There's no documentation on this one.

Can someone enlighten me? Also, we should fix the docs.

[shonfeder]

I think @konnov is most familiar with the profiling?

[konnov]

Ugh, I am actually not sure about the connection between these two flags. This needs some archaeology.