Include `tar` in the "amazon/aws-cli" Docker images

**Is your feature request related to a problem? Please describe.**
Partially. Using the now available aws-cli Docker container doesn't really save us anything over building one manually.

Being able to easily tarball files before sending them to things, such as S3, is a common use case and its absence makes using the prebuilt container pretty worthless (in our use case). We currently are building an in-house container with tar and aws-cli to handle these jobs. Now, we'd have to build another based off of the official image which doesn't really save and/or gain us anything. The draw of using a container like this would be for the drop-in simplicity of deploying to AWS.

**Describe the solution you'd like**
Add tar to the base aws-cli Docker container.

**Describe alternatives you've considered**
We currently are building a custom Docker container with Python, aws-cli, and tarball for handling deploying assets to S3. We'd like to not have to maintain this custom container every time AWS CLI is updated.