[REQUEST] Make it work within a virtualenv

Is your feature request related to a problem? Please describe. I tried to install this in a virtualenv, like I install Python packages in general. I could, but it crashed with an error:

Traceback (most recent call last):
  File "/home/faassen/.virtualenvs/pytools3/bin/bpytop", line 5, in <module>
    from bpytop import main
  File "/home/faassen/.virtualenvs/pytools3/lib/python3.8/site-packages/bpytop.py", line 205, in <module>
    for td in site.getsitepackages() + [site.getusersitepackages()]:
AttributeError: module 'site' has no attribute 'getsitepackages'

The reason is because virtualenv don’t (and I think cannot) support getsitepackages:

https://github.com/pypa/virtualenv/issues/737

Describe the solution you’d like

I would like bpytop to work in a virtualenv. From the code it looks like the sitepackages are consulted to figure out to load up some kind of theme. Perhaps using a setuptools entry point would be a more compatible way to pick up theme packages that doesn’t require this low level access?

https://setuptools.readthedocs.io/en/latest/setuptools.html#dynamic-discovery-of-services-and-plugins

Describe alternatives you’ve considered

I considered installing it in my system Python directly but I try to keep this clean of custom installations as much as possible.

[aristocratos]

That seems to be working. Will be in next update.

[aristocratos]

@faassen Should be fixed in v1.0.26

Reopen this otherwise.