Add autogenerated license information for rootfs.ext2

[diegonehab]

As we prepare to offer rootfs.ext2 as packages, we will have to refer to some place where users can check the licenses of all packages installed inside it. This PR creates and exports a new artifact that allows for the following release notes to be added to packages:

The root filesystem for the Cartesi Machine Emulator provides a default filesystem that can be
used to boot Linux in the emulator. This package installs what is, essentially, a Docker image
converted to an ext2 filesystem image. The license shown for the package is what amounts to the
license of the associated Dockerfile. The image, in contrast, includes a variety of packages, each
with its own license. To see a list of packages in the ext2 filesystem image and their
corresponding licenses, please see
https://github.com/cartesi/machine-emulator-tools/releases/download/v0.16.2-test2/rootfs-tools-v0.16.2-test2.ext2.html

[mpolitzer]

Don't we track files in this directory?
Can you confirm you intention by doing this?

[diegonehab]

I think we are making a bit of a mess here. We have a Dockerfile outside the fs/ directory and others inside it. The external Dockerfile does not depend on anything that exists inside the fs/ directory. So as far as it's concerned, it's fine to have fs in .dockerignore. The fs/Dockerfile depends only on fs/Dockerfile itself. So it doesn't really care. If there was some file, say fs/foo.txt on which fs/Dockerfile depended, and if fs/Dockerfile was built from the outside using the outside as the build context, then this .dockerignore would be a problem. We do build from outside using the outside as build context to pick the TOOLS_DEB, but there is nothing inside fs/ that we care about when building rootfs.ext2. Did I miss something?

[mpolitzer]

WIP?

[mpolitzer]

"It's just not a requirement of the build."

Guess not

[mpolitzer]

My suggestion is to do this in two commits instead:
Commit 1) add the original file only
Commit 2) apply the modifications

This way we can find if and where the original authors copyrighted code is by doing a git blame on this file. And additionally remove this comment.

[mpolitzer]

Same suggestion applies to this file.