make qcodes.__version__ lazy

[jenshnielsen]

This speeds up importing qcodes from an editable install with ~ 0.6-0.7 s assuming that you do not actually make use of the __version__ attribute. The downside is that we do lose some of the static typing of this attribute. See inline comments

Edit. Adding a type to __version__ partially resolves this but its probably better to make version an lazily evaluated property and reference that

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.02%. Comparing base (f77c1e0) to head (952ca6a).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5931   +/-   ##
=======================================
  Coverage   71.02%   71.02%           
=======================================
  Files         301      301           
  Lines       31896    31896           
=======================================
  Hits        22655    22655           
  Misses       9241     9241           

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