Caching files directly in the user's home dir

[jonaslb]

Describe the bug
Since 3.0 blosc2 has been dumping a json file to the user's home dir. I understand that this helps blosc start up faster. However, dumping files directly in the user's home dir is not really considered good form. Many users are annoyed by such littering of dotfiles.

On Linux, the XDG spec is a more-or-less accepted standard for where to put data (config, cache etc). There are other standards on Mac and Windows.
I would strongly suggest using a package such as platformdirs to select an appropriate location for cache files (and other files for that matter, if it becomes relevant).

Using that package (or just the xdg dirs), the cpuinfo cache file would be written to ${HOME}/.cache/python-blosc2/cpuinfo.json on Linux (unless the user has configured another cache dir on his system).

To Reproduce
Steps to reproduce the behavior:

1. import blosc
2. file is created in home dir

Expected behavior

Any cache is written into the appropriate cache dir.

Desktop (please complete the following information):

Linux, but the issue would apply on all platforms

[FrancescAlted]

I think this is a good idea. Would you mind providing a PR?