This commit is packing a bunch of changes that went
into RELENG-e2k-workstation during its forked
development; it covers three distinct things:

- boot.conf preparation for firmware to load the image;
- fixup of packages common for e2k images;
- major cleanup of obsolete/unused cruft
  (unified kernel and reliable xorg autodetection
  allow us to move away from canned machine-specific
  configurations for the most part).