Clean up of explicit namespace declaration

[bamsumit]

• explicit namespace declaration cleanup
• unittests runnable from root level or anywhere in tests/
  python -m unittest

[bamsumit]

Copying PyCharm config instruction from here

• put the 'src' directories (e.g., lava/src) of all lava repositories into the PYTHONPATH
• Mark all 'src' directories (e.g., lava/src) as "Sources Root"
• Mark all 'tests/lava' (NOT tests!) directories (e.g., lava/tests/lava) as "Test Sources Root"

[mathisrichter]

Nice!

[mgkwill]

This looks good to me.

Works from the command line as @bamsumit suggested with python -m unittest and in VS Code using . as root of testing.

Thanks @bamsumit for reworking this change from a clean branch and the testing and effort!