* adjust environment to set PYTHONPATH to pick up site-packages
* add more required packages
* add script for subiquity-server, and set PYTHONPATH there,
so that the PYTHONPATH takes effect
* Abstract resource file lookup relative to SNAP
Using SNAP to find the resource files is a bit of an odd requirement for
non-subiquity clients. Start abstracting that away so it's easier to
change later.
Also move loadkeys to lookup from this, since the previous solution is
still a problem for ubuntu-desktop-installer.
* Move loadkeys / configure-apt to bin
loadkeys / configure-apt are in usr/bin only when we specially put them
there by way of snapcraft, which makes things a little harder on
non-subiquity clients. Move them to bin, which is to say don't have
snapcraft put them in usr/bin.
Dan Bungert