Document all cached directories

[ishitatsuyuki]

Currently this is the source for cached directories, however it seems to be way more directories that can be cached. For example, Python page mentions the pip download cache. The npm example indicates "no configuration required", so it's likely that ~/.npm is also cached.

I hope you can arrange the things out and put them together to the main document page.

[oliworx]

Turns out that for PHP project the directory vendor is cached too