Yes it is now available.
Archive will simply hide from project selection drop down. All the data and everything remains same and you can change archive setting anytime to start using project again.
Steps to archive project
Select Administration from top right settings icon
Go to Manage Projects
Select project you want to archive by clicking on settings icon at end of each project.
Choose "Archive Project" option
Please note: Only admins of the projects can do this action. If you are not admin then you will not be able to see these options.