Remove namespace __init__.py

[BenTaylor-TfN]

PEP-420 updates namespace packages to be implicit.
Most work to achieve this was completed in #46.

Coverage was failing due to an empty __init__.py missing from the namespace package. This is a known issue: pytest-dev/pytest-cov#499

The above issue suggests this to solve. However adding the following into pyproject.toml, and removing the __init__.py:

[tool.coverage.report]
include_namespace_packages = true

Results in:

C:\ProgramData\Anaconda3\envs\caf.toolkit\lib\site-packages\coverage\inorout.py:523: CoverageWarning: Module caf.toolkit was previously imported, but not measured (module-not-measured)

And numerous files are missed in the coverage report, implying this argument is having no impact.

Revisit in future.

[BenTaylor-TfN]

Fixed in #27