Fixes #16416: Improve first login experience by auto-redirecting to crea...

At the moment the installer redirects to create project page. However, if MantisBT is pre-installed, the user lands in My View Page without knowing what to do. We should handle the "first login" experience in MantisBT itself rather than the installation and provide a helpful getting started over time. For now, we should start with auto-redirecting to create project page if user is administrator and there aren't at least 1 project in the database.