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 67.09%. Comparing base (07351c1) to head (27fce61).
Report is 2501 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5931   +/-   ##
=======================================
  Coverage   67.09%   67.09%           
=======================================
  Files         352      352           
  Lines       32035    32035           
=======================================
  Hits        21494    21494           
  Misses      10541    10541           

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