services and prereqs, users and groups

This does a lot of things:
  - removes extlinux from stage1
  - removes the CFLAGS for the libnl-tiny patch
  - removes a lot of users and groups from the default files in KEEP
  - introduces the --prereqs option to services scripts
  - moves the installation of many service scripts to their respective packages
   - splits the sshd service to a dropbear and an openssh one, each installed from it's own package
  - renames the 'uucp' group to 'serial'
  - mount /boot with restrictive permissions (700)
  - unmount /proc and /sys in initramfs instead of moving them, removing the need to sed rc.boot