until laboratory is filled with sensible content

It's one of the core applications

We need to unzip th kernel image because there is not one in the
deb package

u-boot needs a cortex M4 to load the DDR PHY training code so there
are no binary blobs in u-boot. This M4 binray lods that firmware

This adds the cortex m4 code that loads the DDR PHY train code.

This moves the fdt_file configuration variable to the board file
with all of the other configuration variable

Add the custom u-boot and kernel for iMX8. Also the kernel must
be uncompressed for u-boot booti to work.

The image build will still pick up 4.15 until we tested 4.16 some more.

Now that we build different boards print out some variables upfront
so builds can be identified quicker.

Make variables can be overridden on the comand line without any
additional fuzz.

We just use the one shipped by Debian so we don't have to maintain
more stuff on the remote end.