Expand, improve, consolidate dockertests

[cerrussell]

• Expands matrix to run everything on all OSes,
• Adds running pytest tests for all os x python-version
• Addresses codec issue in ms_test on Windows,
• Combines ms_test and version_tests2 for efficiency (leaves version_tests separate due to multiple python versions in matrix).
• Adds improved artifacts names so that artifacts aren't written over due to using same artifact name for all runs in matrix

Successful run.

We may want to clarify what is being tested by renaming this workflow and certain steps in the future since Docker and containers don't appear to be involved.

Closes #135

[prabhu]

Wow, superb!