Updated microkernel to build with current Alpine packages.

[jtilander]

Fixed various problems with the image to build:

• Certificates for gems out of date, disabled verification for now
• ipmitool has fallen out of alpine distro, used https://github.com/urzds/ipmitool-docker to build the pkg/ipmitool.tgz file
• Source repro for lshw changed from testing to community (presumably due to the same circumstances as for ipmitool)
• Gems install version changed to 2.3.0

[tjmcs]

I think this looks good, @jtilander, except for inclusion of the tgz file (we generally try to avoid including binaries directly in the repository); is there any way that you can rebase the branch used to submit this pull request so that this file is not included as part of the PR?

[jtilander]

I guess I could remove the .tgz but the project won't build anymore then. Which is a problem, for anyone new trying to actually get a microkernel going it's a bit of a pain to discover and find the different pieces. The .tgz is rather small, and could probably be replaced with a script that generates it based on checking out the dependent git repository.

That being said, I really have no skin in this game anymore since Hanlon didn't seem to actually work in my experiments and I had a couple of similar experiences to building the microkernel after this with little docs and stuff that simply didn't work at all. I've since moved onto evaluating http://rackhd.readthedocs.io instead.