Allow to import multiple projects

Our system to archive projects requires to import the individual projects to a separate instance when they are ready to be archive. Right now, we need to parse and import for each individual projects. This process is very time consuming as the xml parsing only takes around 15 minutes to finish. At this moment, we need to do this for 50+ projects.

What we would like to have is the possibility of selecting multiple projects from the list and let the process running after all validations have been done making sure that there are no configuration problems.