automation: install awscli and python3-boto3 packages
This provides the `aws` command-line utility as well as a Python
library for interacting with AWS. It is useful to have these packages
installed in AMIs so you can easily interact with other AWS services.
Differential Revision: https://phab.mercurial-scm.org/D6914
#require docutils gettext
$ $TESTDIR/check-gendoc fr
checking for parse errors