Exclude tests from wheels

[stefan6419846]

Description

The wheels currently bundle all tests, which just bloats them and usually is of no value for the actual library usage.

Related Issue

Closes #1477.

Motivation and Context

Bundling tests inside wheels is uncommon and just increases the distribution size.

How Has This Been Tested?

Built the package locally using PIP_INDEX_URL=https://pypi.org/simple python -m build . and verified manually that the generated source distribution and wheel file have the expected directories.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have run the pre-commit run command to format and lint.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have added my name and/or github handle to AUTHORS.rst
• I have added my change to CHANGES.rst
• All new and existing tests passed.

[ddabble]

Looks good, thanks! 😊