Switch to src based layout.

[jenshnielsen]

And move tests outside package.

This should fix compatibility with pytest 8 since the tests collected are also the tests that we run. Since the tests are no longer installed as part of the package. It also improves compatibility with editable installs and static tools and brings the package in line with qcodes.

[codecov-commenter]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (88acfe4) 21.88% compared to head (0f82c53) 11.49%.
Report is 5 commits behind head on main.

Files	Patch %	Lines
src/qcodes_contrib_drivers/_version.py	0.00%	1 Missing ⚠️

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #290       +/-   ##
===========================================
- Coverage   21.88%   11.49%   -10.40%     
===========================================
  Files         164      123       -41     
  Lines       19505    16745     -2760     
===========================================
- Hits         4269     1925     -2344     
+ Misses      15236    14820      -416     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.