At the moment, the Web Interface doesn't allow you to create new user accounts in bulk.
However, there is a way to do this using Custom Commands. You can create a Custom Command that will import users from a CSV file located on a network share (using a PowerShell script). The name of the file can depend on the name of the user who is performing the operation. So, an account operator will need to open a CSV file (using, for example, Excel) located on a network share, enter all the data necessary, and execute a Custom Command via the Web Interface.
This approach is a little bit tricky, but will work.