In Ubuntu most perl packages can be installed using apt. To install Future::AsyncAwait use
sudo apt install libfuture-asyncawait-perl
The naming convention is pretty consistent.
With that being said, it doesn't look like Future::AsyncAwait should be required for WeBWorK 2.17. Did you do a git pull on the webwork2 folder? If so, you've updated the code to 2.18, which has significant backend changes and likely will take some work to get working with that machine image. You are better off starting from the 2.18 AMI.