Create a SVN repo with files checked in and a QC log. The purpose of this demo repo is for the user to become familiar with using review functions.
The files checked into the repo are at various stages in terms of their QC needs. This function returns the path to the repo, so that the user can set their working directory to it.
This demo repo is created in the tmp folder, so a new one will need to be
generated whenever the user restarts R.
demoRepo(.project_name)
with_demoRepo(code, .project_name = "abc-123")