lcitool: Drop the 'build' command

Although this used to be useful back in the day when most of our listed
projects (mostly libvirt though) were built in VMs, with the rise of
git forge like services providing containers to build projects from
sources this feature is became less useful. Although having become
obsolete, the biggest problems of this feature were that:

- the extra Ansible layer in form of playbooks abstracted useful bits
  like real-time stdout logging of the build process making debugging
  of a build issue more difficult than if having it done manually,
  especially considering the JSON serialized stderr dump it returns

- project dependencies - in order to built project X, project Y had
  likely to be built prior to project X so that fresh builddeps were
  available at project X's build time. Not only the projects had to be
  named in the exact order they were to be built, but project Y could
  not even specify that it could be built against distro provided
  builddeps if so desired.

- slight changes to the build procedure or tool chains used in the
  respective upstream projects.

Should a build happen in such a VM, each and every project is
responsible to maintain their own build recipes which the user can
happily execute interactively inside an lcitool-prepared VM.

Signed-off-by: Erik Skultety <eskultet@redhat.com>