feat: Project setup

[frgfm]

This PR aims at:

• adding a working module crawler
• adding dependencies for documentation build
• updating readme
• adding unittests
• adding a benchmark script

[codecov-io]

Codecov Report

:exclamation: No coverage uploaded for pull request base (master@f49c15a). Click here to learn what that means. The diff coverage is 42.63%.

@@            Coverage Diff            @@
##             master       #1   +/-   ##
=========================================
  Coverage          ?   42.63%           
=========================================
  Files             ?        8           
  Lines             ?      441           
  Branches          ?        0           
=========================================
  Hits              ?      188           
  Misses            ?      253           
  Partials          ?        0

Impacted Files	Coverage Δ
torchscan/crawler.py	10.98% <10.98%> (ø)
torchscan/modules/__init__.py	100% <100%> (ø)
torchscan/process/__init__.py	100% <100%> (ø)
torchscan/utils.py	21.95% <21.95%> (ø)
torchscan/modules/memory.py	54.94% <54.94%> (ø)
torchscan/modules/flops.py	57.6% <57.6%> (ø)
torchscan/modules/macs.py	61.29% <61.29%> (ø)
torchscan/process/memory.py	73.33% <73.33%> (ø)