Add logging to build-stack-docs
Add logging to build-stack-docs

- Add -v/--verbose command line argument to set the logging level to
  DEBUG; otherwise the logging level is INFO.

- Add logging statements throughout the build pipeline.

- Log the code version. This is useful for debugging in CI.

lsst-sqre/sphinxkit,lsst-sqre/documenteer,lsst-sqre/documenteer