Move the Performance Monitoring guide to somewhere more appropriate

[TimMonko]

🧰 Task

https://napari.org/dev/howtos/perfmon.html

By the time I was advanced enough to make use of something like Performance Monitoring, I was no longer checking in 'How-to-Guides', so I didn't even know this existed until pointed out in napari/napari#8118 (comment)

I think it should either be moved to in-depth explanations or the contributing guide, not sure which.

Regardless, this is also a problem partly solved by #770

[willingc]

Contributing guide probably is the best place. In-depth explanations for sections that help users improve performance of their code.

[psobolewskiPhD]

I think it might need an update too, because that chunk code isn't a thing anymore?
Would be nice to have a few config files somewhere (in napari/napari repo?) for testing stuff.

(note the "location" of this is based on the type of content, rather than the topic, but i do agree it's not a great spot for it)