[cooker] Introducing mkefiboot (yes, the one from lorax, now available as a standalone tool!)

Hey all,

So I've been trying to figure out how to support UEFI image builds on
non-RH/Fedora systems using livecd-tools for some time now. However,
historically, livecd-tools has been tied to Weldr's Lorax[1] for
producing UEFI-enabled media. Specifically, the mkefiboot tool shipped
in lorax. In order to support this properly on Mageia and other
non-RH/Fedora systems that are compatible with livecd-tools, I've
split out the mkefiboot tool into its own project as a "friendly
fork": Overview - mkefiboot - Pagure.io

In case you're wondering, I had tried to avoid doing this. I've been
happy with the Lorax team's maintenance of the tool, and I preferred
any path that would have let me continue to rely on them for this
aspect.

I'd briefly discussed with the Lorax folks about having their
implementation split out into its own repository, but they were not
interested in doing so. Consequently, I started looking into
alternatives to resolve the situation, including methods to remove the
mkefiboot dependency.

Unfortunately, reimplementing the logic would not be fun or desirable.
Moreover, I still want to remain broadly compatible with the Weldr
team's implementation, especially as they are maintaining it for Red
Hat/Fedora systems, which remains an important target to support.

So, I split out the code into its own project for usage on systems
that aren't Red Hat/Fedora-based. I do not have any intent to package
this up for Fedora. This will be landing in Mageia Cauldron and
OpenMandriva Cooker shortly, and their livecd-tools packages will no
longer block producing images with UEFI support.

Now, does this mean I hold any resentment or anger at the Lorax folks?
Far from it! The Weldr group is doing some seriously cool things[2],
and I look forward to seeing how things progress. For all intents and
purpose, I regard the Weldr/Lorax team as the proper upstream. If
there are relevant changes to pull in, I'll do my best to incorporate
them into this code.

However, this is code that doesn't generally change much, so don't be
surprised if there isn't much (if any) activity on the codebase.

So, does this change anything for the vast majority of livecd-tools
users? Nope! But it's another brick on the road toward livecd-tools
fully supporting any distribution that uses the DNF package manager.

[1]: Welcome to Lorax's documentation! — Lorax 31.7 documentation
[2]: https://weldr.io/