Improve device information in netket.tools.info

[femtobit]

This fixes as small display bug in netket.tools.info:

Before:

$ python3 -m netket.tools.info
[...]
# MPI4JAX
  - HAS_GPU_EXT      : <function has_cuda_support at 0x...>
[...]

After:

$ python3 -m netket.tools.info
[...]
# MPI4JAX
  - HAS_GPU_EXT      : True
[...]

Edit: Since I already had that file open: I've added some code to print nicer looking device information:

# Jax 
  - backends         : ['cpu', 'gpu']
    - cpu            : ['<0: cpu>']
    - gpu            : ['<0: Tesla V100-PCIE-32GB>', '<1: Tesla V100-PCIE-32GB>'

[github-actions]

Hello and thanks for your Contribution!
I will be building previews of the updated documentation at the following link:
https://netket.github.io/netket/preview/tools.info

Once the PR is closed or merged, the preview will be automatically deleted.

[codecov-commenter]

Codecov Report

Merging #1084 (bad6155) into master (f55de83) will decrease coverage by 0.21%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1084      +/-   ##
==========================================
- Coverage   82.04%   81.83%   -0.22%     
==========================================
  Files         204      204              
  Lines       12125    12127       +2     
  Branches     1812     1813       +1     
==========================================
- Hits         9948     9924      -24     
- Misses       1743     1768      +25     
- Partials      434      435       +1     

Impacted Files	Coverage Δ
netket/tools/info.py	88.77% <100.00%> (-1.85%)	⬇️
netket/tools/_cpu_info.py	52.94% <0.00%> (-35.30%)	⬇️

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[PhilipVinc]

Lovely!