Add tuftool dockerfile

[stockholmux]

Issue #, if available:

n/a

Description of changes:

This PR adds a very simple Dockerfile for tuftool

This solves a problem for Bottlerocket users who have been challenged to download all the dependencies for tuftool just to get an image. Additionally, this potentially avoids the need to create a cross compiled binary (see #662)

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[webern]

This seems like a good idea to me. I suspect you have heard from users that they don't like installing Rust to use tuftool? I think we do want to provide binary releases in the future, but this is an easy fix for now.

I need to make sure this works on Linux.

[stockholmux]

@webern That's right - users don't want the Rust tool chain in every situation. A binary would be more elegant but it's a lot more work and I'd like to give folks a way to use tuftool ASAP.